If you can get an airplane in the ballpark of a passenger car, you are doing OK.

An airline ticket is break-even on fuel consumption vs. driving long distances as long as the plane is pretty fuel (they usually are) and the driver is sole occupant (often the case).

The airplane's a lot faster on a TRANSCON, but anywhere you can drive to in a day, you'll save a bunch of money by driving if you have a family of five.