Recap of Airplane II: The Sequel.
The first passenger shuttle to the Moon, named the Mayflower, is ready for its maiden voyage, but all is not well with the spacecraft. Meanwhile, Ted Striker, who helped test pilot the vehicle, is committed to a mental hospital on the strength of a Kangaroo Court frameup after he tried to blow the whistle on its design problems. Learning of the shuttle's impending launch, he escapes the hospital and races to the airport in an attempt to stop it.
When he gets there, he meets Elaine, who has moved on since the trial and found a new boyfriend, Roger. They are crew members on the lunar shuttle and refuse to believe Ted's warnings. He gets aboard by means of a scalped ticket and the shuttle sets off. Naturally, partway through the voyage its computer systems short out, leading the onboard AI, R.O.K., to steer the shuttle drastically off-course, while adamantly denying that anything is wrong.
When the pilots attempt to disconnect R.O.K., he murders them, forcing Elaine to admit that Ted was right and putting him right back in the cockpit. The first order of business is to destroy R.O.K., which is accomplished by use of a bomb that a suicidal passenger conveniently brought onboard. That problem solved, they use the shuttle's experimental "Worp" drive to return to the Moon at Ludicrous Speed.
The commander of the lunar base, Buck Murdoch, is also an old war commander of Striker's, and naturally is not too pleased to hear from him, but in an inversion of the previous film, Ted knows what he's doing and Murdoch proves to be an incompetent buffoon. Another crash-landing ensues, everyone's saved, and Ted and Elaine finally tie the knot.