How does one pray during an airplane flight?

Assalam 'alaikum Consider that my flight takes off at 6:00 PM which is normal time for Jama'at of Asr (عصر) prayer in my city these days, and the flight is supposed to take 4 hours. This means that at the time of Maghrib (مغرب) prayer I'll be on board. So, how can I pray while in an airplane? It is a moving thing. Also, according to which time would I pray? According to my city's time or the one my plane is flying over at that time?