Israelis clap (and sometimes cheer) when the plane they are on touches the ground. This is to thank the pilot for doing his or her job properly and not killing them in a flaming plane crash. I've read somewhere that this is because people are "happy to return to their homeland", but let me tell you, most Israelis never are. They are, however, happy to have not died on the plane. You'll hear a lot of clapping and cheering if the flight was particularly bouncy.
Some Israelis are embarrassed by this and think it's a bit primitive or something, but I actually think it's a nice, sweet thing to do. Any landing I can walk away from is worth some applause as far as I'm concerned, and clapping is far better than most stuff Israelis do on flights.