Originally posted by kopking
plus you cant shoot the plan(e) down on first level
Of course you can.

***possible spoiler***
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Sorry, had to lift this from gamespot; it\'s been a while since I have played TM:B.
Secret--Unlocking the Yellow Jacket Vehicle
To unlock the available car in the Junkyard level, you must first open the entrance into the sewer. To do so, spot the airliner that circles the junkyard. You can\'t get close to the airplane, because it flies well beyond the outskirts of the junkyard fences. Approach the edge of the junkyard and aim toward the plane; launch a fire or homing missile when the plane is in view. The missile should impact with the plane. If the missile strikes the plane, you will spot the explosion and flames as the plane starts to crash. If you miss, simply aim and shoot again.
You must not have any enemy cars within view or the fire or homing missile will lock onto the enemy car and not the plane. So you aren\'t under constant attack, wait until you have destroyed several cars before you attempt to take down the plane. The plane crashes against the warehouse\'s supports on the opposite end from the repair bay. Don\'t be on the crash site when the plane comes down or your car will be destroyed.
Explore the sewers to discover the hidden vehicle, Yellow Jacket.
The crash creates a hole leading down beneath the warehouse. Follow this underground tunnel as it winds down into a circular room. Make sure you pick up the power-ups along the way, including a health power-up. Once inside the circular area, locate the console against the middle pillar (it\'s actually a lift housing the secret car). Destroy the console with any weapon or by ramming it with your vehicle. Once the console explodes, the pillar lowers and reveals Yellow Jacket, the Junkyard\'s secret car and character. You can exit the sewers the way you came in or take a shorter route back outside; locate the shorter route exit near the console.