In the opening scene of The Adventures of Buckaroo Banzai Across the Eighth Dimension, Team Banzai is testing the Oscillation Overthruster's ability to enable Buckaroo's jet car to move through the empty space between subatomic particles, seemingly traveling through a small mountain unharmed. However, it's clear from the reactions of the press and government representatives in attendance that only Team Banzai knows beforehand about the Overthruster and the real purpose of the test.
The cover story--the supposed purpose of the test--is never made clear in dialog as far as I can tell. From an unofficial screenplay here:
GENERAL CATBURD: I'm teeing off in an hour and a half. What's this jalopy supposed to do, anyway? SENATOR CUNNINGHAM: Five hundred miles an hour. SECRETARY OF DEFENSE: Oh, Senator, you're so gullible.
So is the cover story merely that Team Banzai is seeing how fast the jet car can go? How would that fool anyone? It's a pretty minor job for a person who is as busy and important as Buckaroo Banzai. Maybe he's trying to break the land speed record for jet-powered wheeled vehicles, but, assuming the events of the film take place in the mid-'80s when it was made, the record in that category at the time was well over 600 mph, so 500 mph is nowhere close.
Is there an in-universe explanation in the novelization, the screenplay, or other supporting material, for a more convincing cover story? What do the government officials and press believe they are watching when the jet car starts off, before Buckaroo swerves away from the "official" course and heads towards the mountain to test the Oscillation Overthruster?