Really, there was no point in Murphy hijacking Blue Thinder at all
Apparently, Murphy had two goals:
1. Get the tape to the media
2. Destroy Blue Thunder
Rather than involving Kate and calling attention to the bad guys about what he was up to, why didn't Murphy just secretly drive over himself to the dumpster, retrieve the tape and QUIETLY bring it to the media himself? More chance of success there.
As far as destroying Blue Thunder -- what good would that do? They can always just make another one.
Not to mention all the destruction he could've avoided, as well as the trouble he must've been in after the movie.
I realize we're cutting out the best part of the movie here, but if you're gonna have Murphy in the air with Blue Thunder, at least make his reason for doing so make more sense, more of a neccessity.