Choosing between a return ticket, two one-way flights and an open-jaw itinerary can change both the price and the risk of a trip. This guide gives you a repeatable way to compare the total cost, flexibility, baggage arrangements, airport changes and protection attached to each option before you book.
Overview
A return flight usually covers the outward and inbound journeys on one booking between the same airports. Two one-way tickets are booked separately, either with the same airline or with different airlines. An open-jaw itinerary combines flights where the return starts or ends at a different airport from the outward journey—for example, flying from London to Barcelona and returning from Madrid to London. The overland journey between Barcelona and Madrid is arranged separately.
There is no universal cheapest option. A return fare may be the best value on routes where airlines price the outbound and inbound sectors as a package. Two one-way tickets can be useful when airlines sell each direction competitively, when your dates differ, or when you want to return to a different UK airport. An open-jaw booking can avoid backtracking, but the saving must be measured against the cost and time of travelling between airports or cities.
For a fair comparison, look beyond the headline airfare. The relevant figure is the total trip cost:
Total trip cost = flights + baggage and seat fees + airport transfers or surface travel + overnight costs caused by the itinerary + change or cancellation risk.
That final factor is difficult to price precisely, so treat it as a decision point rather than pretending it has a fixed value. A slightly cheaper itinerary may not be better if it uses separate tickets, tight connections or restrictive fare rules.
| Booking option | Price potential | Flexibility | Main risks to check |
|---|---|---|---|
| Return ticket | Often competitive when the same route and dates price well together | Depends on the fare rules; both sectors may be linked | Missed-flight consequences, restrictive changes and limited airport choice |
| Two one-way tickets | Can be cheaper when different airlines or airports offer better fares | Usually easier to mix dates, airlines and airports | Separate-ticket protection, duplicate baggage charges and incompatible schedules |
| Open-jaw itinerary | May reduce backtracking or create access to a cheaper airport | Good for multi-city trips, but the surface leg is your responsibility | Airport transfers, ground transport, extra nights and missed-connection exposure |
How to estimate
Use the same passenger details, dates, cabin and baggage requirements for every search. Then test the options in a consistent order.
- Price the standard return. Search the exact UK departure airport, destination airport and travel dates. Record the fare, flight times, stops, included baggage and the conditions for changes, refunds and missed sectors.
- Price each direction separately. Search the outbound as a one-way flight and the inbound as a one-way flight. Try the same airline first, then compare different airlines and reasonable alternative airports. Add the two fares together rather than comparing only one leg.
- Test an open-jaw search. Use a multi-city search if the comparison site supports it: UK airport to the first destination, then the second destination back to the UK. If the search cannot show the required combination, price both one-way flights manually.
- Add unavoidable extras. Include checked baggage, cabin bags where charged, seat selection if required, booking fees, airport transfers and the cost of travelling between open-jaw destinations.
- Review the connection structure. Mark whether each itinerary is one booking or separate tickets. A single booking may offer a clearer process when the airline changes a flight, while separate tickets leave you responsible for allowing enough time and handling disruption between bookings.
- Compare like with like. A direct flight should not be treated as equivalent to a long connection simply because the fare is lower. Record total journey time, arrival time and transport to or from each airport.
A simple spreadsheet helps. Create one row for each option and columns for fare, bags, seats, transfers, surface travel, overnight stay, total cash cost, booking type and key restrictions. The cheapest airfare is only the winner if it remains cheapest after these columns are completed.
When using a flight comparison site UK travellers should check the final price on the airline or booking provider's payment page before deciding. Prices, availability and included services can change between the results page and checkout.
Inputs and assumptions
The quality of the comparison depends on the inputs. Write these down before searching:
- Airports: Include the cost and time of reaching alternative airports. London, Manchester, Birmingham and regional airports can produce very different total journeys.
- Dates and date range: If your schedule allows flexibility, test each option across the same range. Do not give one booking type more favourable dates than another.
- Baggage: State how many cabin and checked bags each traveller needs. Airline baggage fees can erase an apparent saving on a one-way fare.
- Passengers: Search for the correct number of adults, children and infants. A low fare may apply to only one available seat.
- Airline and fare type: Note whether the fare is basic, standard or flexible, and what is included. Names and rules vary, so read the conditions attached to the specific fare.
- Connection tolerance: Set a minimum acceptable connection time based on the airports, terminals, immigration requirements and whether baggage must be collected and checked again.
- Protection structure: Establish whether the flights are on one booking reference, separate booking references or a formal multi-airline itinerary. Do not assume that a comparison site's combined result creates one protected ticket.
Missed-flight rules deserve particular attention. On some return bookings, failing to take the outbound sector can affect the remaining itinerary under the ticket's conditions. With two one-way tickets, a missed outbound normally does not automatically cancel a separately booked inbound, but you still lose that flight and may need to buy another ticket. Always verify the rule for the fare you are about to purchase.
Baggage rules also need a sector-by-sector check. Two one-way tickets may require paying for bags twice, while an open-jaw trip may involve different allowances on different airlines. If your itinerary changes airports, include local rail, coach, taxi or car-hire costs in the calculation rather than treating the surface journey as free.
Worked examples
Example 1: A conventional city break
Imagine a traveller needs to fly from a UK airport to one European city and return to the same airport on fixed dates. They first record the return fare, including the required bag. They then price the same outbound and inbound flights as separate one-way tickets, adding any one-way fare differences and baggage charges.
If the return booking is cheaper and has suitable times, it is the straightforward choice. If the two one-way tickets cost less, the traveller should still compare change rules, booking references and what happens if the outbound is delayed or missed. For a short city break, a saving may not justify a much later arrival or an airport transfer that takes several hours.
Example 2: Different airlines in each direction
Suppose the best outbound fare is with one airline and the best inbound fare is with another. The traveller adds both one-way fares, baggage, seat selection and any payment or booking charges. They then compare that total with a return fare on either airline.
The two one-way option may offer a useful price or schedule advantage, but it is a pair of separate contracts unless the checkout clearly creates one combined booking. The traveller should leave more resilience around each journey, keep booking confirmations separate and understand that a disruption to one ticket may not trigger a solution for the other.
Example 3: An open-jaw holiday
Consider a trip that starts in one city and finishes in another: UK airport to City A, then City B back to the UK. The calculation has three parts: the outward flight, the return flight and the journey between City A and City B. Add accommodation if the flight timing forces an extra night, plus transfers to and from the chosen airports.
An open-jaw itinerary can be the cheapest way to book multi-city flights when it avoids returning to the starting city. However, compare it with a normal return plus a separate domestic or rail journey. The better option may be the one with the lower total time and fewer points at which a delay can disrupt the plan.
When to recalculate
Re-run the comparison whenever a key input changes. This includes new travel dates, a different number of bags or passengers, a change of UK departure airport, a new destination combination, or a fare drop alert that reveals a different airline or route. Recalculate after adding seat selection, checked luggage, airport parking, rail travel or an overnight stay.
It is also worth checking again before payment if you have been searching over several days. Availability can change, and the cheapest fare bucket may no longer be offered. If an airline changes its schedule, repeat the comparison rather than assuming the original return, one-way or open-jaw arrangement still works.
For a practical final check:
- Save the final price and fare conditions for every serious option.
- Confirm the number of booking references and whether the itinerary is one ticket or separate tickets.
- Recheck baggage, airport, terminal and transfer requirements.
- Calculate the full door-to-door cost, not only the airfare.
- Choose the option whose price, flexibility and disruption risk fit the trip.
For more detail, compare the real cost of airline baggage fees, review multi-city flights from the UK, and check how layovers and connecting routes affect your decision. Repeating this process whenever prices, dates or travel requirements move will give you a more reliable answer than relying on a headline fare.
