iPhone 4-problems with app store

I keep getting errors when trying to use the app store. The message says "cannot connect to app store", or if it finally does connect, the download won't start and I get a message saying "the app will be available later when you connect to itunes via your computer". (paraphrasing of course, but you get the idea)The only thing I've found that helps, is toggling airplane mode. That helps for a short time, but then the problem just comes back. Anyone run into this, and if so, is there a fix? Is the store just being flooded with traffic maybe?