Airports had three of their busiest days since the beginning of the coronavirus pandemic over the Labor Day holiday, a hopeful sign for airline investors waiting for travel to rebound.

The Transportation Security Administration screened 968,673 travelers on Friday, Sept. 4, the highest single-day number since March 17. Monday was also encouraging, with 935,308 travelers going through security.

A traveler with a mask on makes her way through an airport.

Image source: Getty Images.

The numbers are a dramatic increase from early April, when fewer than 100,000 passengers were screened on some days, but remain less than half of airport traffic a year prior. The travel that is happening appears to be primarily leisure traffic.

The increase is good news, but airline investors need to be careful not to get ahead of themselves. Labor Day marks the end of the summer vacation season, and with business travel still anemic, the airlines are expecting a drop in volume heading into the fall.

The industry is planning to cut thousands of jobs in early October. The airlines are not expecting travel volume to return to pre-pandemic levels until 2022 at the earliest, and that is assuming a COVID-19 vaccine becomes available in the first half of 2021.

For those interested in buying in, caution is still warranted. Investors should focus on the industry's top names, including Southwest Airlines (NYSE:LUV) and Delta Air Lines (NYSE:DAL), which have the best chance of surviving a prolonged period of turbulence.

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