Daniel is right in that Flash content won't work directly on your iPad's Safari, but Flash contents can actually be turned into iPhone and iPad apps (and even Android) very easily and it's a fine tool for building cross platform 2D game contents. Apple has long lifted the ban on cross platform tools and external runtime. We have published two apps using Flash and they work great.

Because at one point Apple started banning all use of virtual machines and external runtime, including Air and it has gotten a lot of publicity. Since then they have reverted their policy but a lot of people who didn't plan to use Air in the first place continued to hold on to the old info. One of our my apps uses Air so I have been following this very closely.