Low fares frequently arrive at airports an hour or more from the city named on the ticket. The arrangement lowers the airline's costs and moves part of the journey onto the passenger.
Airport charges differ enormously
Airports levy fees per passenger and per aircraft movement, and the difference between a congested primary airport and a quiet secondary one is substantial.
On a short flight sold cheaply, these charges are a large share of total cost, so the choice of airport can determine whether the fare works at all.
Secondary airports also compete for traffic and will discount further, sometimes structuring charges to reward airlines that add frequency or hold a base there.
Quiet airports allow faster turnarounds
Without queues for stands, runways or ground handling, an aircraft can be unloaded, cleaned, reloaded and airborne again in a fraction of the time.
Faster turnarounds mean more flights per aircraft per day, which spreads the fixed cost of owning that aircraft across more revenue.
This effect is often larger than the saving on charges. The airline is buying schedule efficiency, not just cheaper parking.
The transfer cost is real and uneven
A coach or train to the city centre carries its own fare and its own hour, and for two or more travellers the total can rival the flight itself.
Timing matters as much as price. Late arrivals may find the connecting service has finished, which converts a cheap flight into an unplanned taxi or overnight stay.
Comparing airport pairs rather than city names is the only way to see the real cost, since the published fare deliberately excludes this leg.
Naming conventions overstate proximity
Airports are frequently marketed under the name of a city they are nowhere near, using the nearest recognisable destination rather than the actual location.
The practice is long established and mostly legal, provided the distance is disclosed somewhere in the booking process.
Checking the airport code against a map before booking takes seconds and resolves the ambiguity that the route name is designed to create.
When the secondary airport is the better option
For travellers whose destination is outside the city, the smaller airport can be closer and faster, turning the supposed drawback into an advantage.
These airports are also quicker to move through on arrival, with shorter walks and lighter queues, which recovers some of the transfer time.
The calculation depends entirely on where the trip actually ends. Treating the flight as one component of a door-to-door journey gives the honest comparison.