Airplanes sometimes leave white lines in the sky, called contrails. But what's the science behind why they form, and are they ...

Ever wondered about the white lines planes leave behind? Known as contrails, they form when hot engine exhaust meets cold, moist air, turning water vapor into ice crystals. While they often vanish ...

The Federal Aviation Administration is investigating an incident involving two planes at Sky Harbor on Jan. 11. ... and it involved United Airlines Flight 1724 and Delta Air Lines Flight 1070.