If you're talking about the cage in the top right screen with the spikey red ball that blows up...don't go that way.
From the start screen, go through the cage/screen in the bottom left, after you've collected the extra fuel pack in the screen directly above the start screen.
If the cage in the bottom left of the start screen is the one you're having trouble with, just try to go nice and slow, and don't rush.
Hope this helps.