FRG's purpose is not to provide scheduled airline service.

http://www.republicairport.net/index2.htm
<<Since 1969, Republic Airport has accommodated the area’s need for an airport devoted to flight training, private and corporate aircraft, as well as charter and regional commuter operations.>>

Not saying this couldn't change of course; perhaps Skybus could be granted an exemption, but the situation is not so simple (I don't think) as simply no airline would consider the location, terminal, runway etc.....

Tom