When the flying car episode aired, it ended with the vehicle failing, and showed Jesse blowing it to smitherines. However, in later aired episodes, towards the end of the intro. to the show, you see the same car taking off of a runway? I'm a lot of people, such as myself, really WANTED to see that car fly, regardless of whether it failed or not. But, since you already teased the attentive viewers with your show introduction, proving that it was indeed finished after failing the competition, why don't you just put the entire flight, however short or long it was, on an episode? Especially since apparently the series is ending, and once that happens, it's likely that we'll never get to see it.

The last show of that season ended with the Panoz Esperante/Airplane that WAS a successful build...
Jesse flew it at Kitty Hawk...

I think that you may have shows confused....

The last Monster Garage that was shown in the USA was a tribute show...

In fact, Jesse was on Letterman, a few days before the episode aired on Discovery, showing the car in the air. The car/airplane didn't have all the controls needed for sustained flight, so they only went for the straight line flight. Build was sucessful.