NO ESCAPE FROM HEAT: Heat makes flying airplanes much more difficult! Because, hot air is less dense than cold air, its molecules zipping around at higher speeds, meaning planes have less lift when the temperature rises. That makes it harder for them to take off and stay aloft. Airlines often choose to delay flights or unload passengers and luggage to shed weight from planes when the temperature climbs too high, leading to cascading schedule disruptions, along with passengers occasionally being trapped for hours on runways inside roasting aircraft. So if you are planning to take a trip in summer heat, be aware. The era of global boiling is here! There’s no escape. (Comment by: Stephen N.R., Senior Associate Editor)