There are some caveats: Airlines have a legitimate safety reason for keeping seats in the upright position at certain times, and mealtime is no exception. A good rule of thumb is to avoid reclining your seat until after meal or beverage service.
Before pushing your seat back, though, be aware of your surroundings. If the person behind you is 6-foot-3-inches tall, take one for the team.
Now what about the person in front of you who insists on reclining at an inappropriate time? I always suggest quietly asking the flight attendant to step in, or you'll risk starting a war.
Or try this little trick: There's a pocket-size gadget called the Knee Defender that you simply stick onto your tray table. It prevents the seat in front of you from reclining (you didn't hear it from me).
If you've got long legs, you might find that it's worth paying for economy plus seats. They have a bit more legroom. Delta, United (and soon, Continental), JetBlue and Virgin America all offer this option on certain flights. To find out which routes, check out the website seatguru.com, which shows the seat configurations of all airlines based on the type of airplane. Even better, it analyzes good and bad seats. According to their experts, a good rule of thumb is premium seating is only worth it if the cost is no more than 15 percent of a standard economy ticket.
What's the flight attendant's role on a plane?