Carla took the bus. Heck, Loretta and Nick took the bus from New Jersey to Cheers for the dance contest.
In an earlier episode, Carla took a trip to Graceland. Either the thought of "seeing" Elvis was enough to overcome her fear of flying, or she took a rather long bus trip from Boston to Memphis.
Referring to the critic who gave Cheers a good review:
Rebecca: I did not sleep with him!
Carla and Frasier did not board a flight to Seattle.
It was the end of his class. It was a short flight to help the patients overcome their fear. You'll notice in the very next scene, Carla is on the phone and informs Eddie she is flying out tomorrow.
George Wendt actually directed this episode. It the only episode directed by him.
Carla and Frasier board a flight to Seattle. Was Frasier thinking of visiting Niles and Martin?
Norm: "The Bobbsey Twins go to the brewery. Lets just cut to the happy ending." The Bobbsey Twins are a series of novels written by multiple authors under the pen name Laura Lee Hope. They describe the adventures of two sets of fraternal twins, and have been published since 1904.