The headlines over recent weeks about soaring temperatures causing flight cancellations have meant frustration and shock at how it can be too hot to fly. How are airports and airlines handling the situation?

Much of the news has centered around Phoenix Sky Harbor Airport in Arizona. Local temperatures have soared close to 120 degrees during intense summer heat affecting the whole Southwest region. As a result, the airport saw numerous cancellations and delays of flights over a few days, simply citing the temperatures as the reason aircraft could not fly.

Much of the disruption was to regional flights flying within Arizona and nearby states where temperatures are of a similar intensity, with most longer-distance flights operating to normal schedules, or with a slight delay. Regional aircraft ply the shorter routes, and American Airlines — the largest operator at Phoenix issued a statement saying its Bombardier CRJ regional aircraft have a maximum operational temperature of 118 degrees, so were unable to take off or land during some periods.

The effect of the heat on the ground has also added to the delay. The temperature of the tarmac at Sky Harbor reached almost 170 degrees, meaning dangerous working conditions for ramp workers, refuelers and the equipment they use. They also have to deal with the relentless sun and heat from above throughout their shift.

Rumors spreading about tarmac melting and airplane tires bursting seem to have been somewhat of an urban legend, with no such occurrences reported or likely. The truth is that pilots rarely have had to deal with such high temperatures, and their operating procedures do not cover them.

Aircraft operating in high temperatures have to deal with less dense air. Combine that with the altitude above sea level that Phoenix is situated, and aircraft can struggle to generate enough lift.

Longer takeoff runs are necessary, and often the answer is to offload passengers and cargo to reduce weight. The alternative is to delay the flight to a cooler part of the day, as has happened in many cases. This was echoed at other airports across the region, including Las Vegas McCarran, which saw some delays.

Sky Harbor's runways are of ample length to cater for longer takeoff runs for its usual ambient temperature, but the regional jets in question have less thrust than the larger mainline aircraft.

American Airlines has worked hard to accommodate passengers held up by the delays, and in some cases substituted mainline aircraft to cover for the grounded regional jets, allowing some flights to go ahead.

Phoenix Airport itself has largely downplayed the events, directing passengers to speak to their airlines and no doubt hoping for a reprieve soon. Previous notable events in the 1990s and early 2000s also saw cancellations at the airport, and with summer upon us there can be no promises that this situation is over.