Someone at Apple certainly didn’t think about iMessage and Airplane mode with Wifi turned on. Since iMessage requires an internet connection, a Wifi connection would suffice. (As you can see, I’m on AT&T’s 200MB/mo plan)
Also, download Operation Ajax, a comic depicting the actual 1953 US covert operation in Iran, in the iPad App Store for free while it lasts. It’s a great narrative of what went on in the 60’s. The comic lets on the United States’s dark side; its habit of playing chess with foreign nations.