SPOILER - CHEAT
There's two cheats I know of - one to get you to 114, and one that actually never ends.
To get to about 114, pick up the plane and drag it to the top left of the screen. Release the mouse and move AROUND THE OUTSIDE of the game window to the right hand side. Put the mouse back on to the game window somewhere in the shaded area above the skirting board. It thinks that you have moved the distance in one time unit and launches it at great speed. You'll need to experiment to find out exactly where to re-introduce the mouse to get the best results. And I do mean 'need' as those of you already addicted to this game will know!!
The second cheat then involves zooming in on the metre scoreboard which confuses the 'plane has landed' check, and it seems to keep on ticking up.