I have exactly the same symptoms discussed on the forum. I have a 17" 2009 MacBook Pro and I had the airport off and cannot be turned on after the machine was suspended. Sometimes on power-up, I get airport card not installed. Sometimes, it just works and I cannot detect any pattern for the machine's behavior. I am nearly ready to take it to the apple store since it is under warrantee. Then it works for an extended period of time. I have really enjoyed the machine. I hope I am not headed for a number of repairs for this symptom.
What's interesting is that I have a 13" and I have similar problems. After waking up from hibernation or sleep, Airport might or might not turn on. If it's the latter, it'll say either "Airport Card not installed" or "Turn Airport on". Once again if it's the latter, I try and click it and nothing happens. Have you also been experiencing random freezes? Also, sometimes it won't start up, and I have to force shut it down while it's trying to start up. I have a Genius Bar appointment tomorrow, so will keep you informed