At most large American airports there is a second, quieter set of buildings on the far side of the field. They handle general aviation, and the service they sell is mostly the removal of waiting.
The airfield is shared, the buildings are not
Private aircraft use the same runways, the same air traffic control and the same weather as scheduled flights. What differs is everything between the curb and the aircraft door.
A fixed base operator provides ramp space, fueling, ground handling and a passenger lounge, functioning as a small terminal serving a handful of people at a time rather than thousands.
Because the volumes are low, the building can be sized for peaks that would be impossible to staff in a commercial terminal, which is what produces the sense of emptiness.
Time is compressed at both ends
The core saving is not speed in the air but the elimination of queues on the ground. Check-in, security processing and boarding collapse into a short walk across a ramp.
Departure timing becomes flexible in a way scheduled flying cannot match, because the aircraft is not part of a rotation that must reach five more cities before the day ends.
That flexibility is the actual product. A traveler is buying control over the schedule rather than a faster aircraft, since cruise speeds are broadly comparable to airline jets.
The operator sits between several businesses
Fixed base operators earn from fuel sales, hangar rental, handling fees and ramp charges rather than from ticket revenue. Fuel is often the largest single line.
This is why an operator may waive handling charges when an aircraft uplifts a substantial fuel load, and why identical services can be priced very differently across two operators on the same field.
Aircraft owners and charter operators shop between them, so the competition is between facilities on one airport rather than between airports.
Access to airports changes the map
Smaller general aviation fields sit closer to many towns than the nearest airline airport, so a private flight can end far nearer the destination.
The saving is in ground transport, which on a regional trip can exceed the flying time. That is often where the case for private travel is strongest.
Runway length, approach equipment and ground services still constrain which aircraft can use which field, so the choice is narrower than a map suggests.
Congestion still applies
Private aircraft queue for departure with everyone else and hold in the same sequences when weather reduces capacity. The private terminal does not confer priority in the air.
At slot-controlled airports, general aviation access is limited and can be the first thing constrained on a busy day, which is why operators often plan around secondary fields.