It's not your imagination: Planes are dirtier

Early in the pandemic, airlines began marketing the cleanliness of their planes. They tried to put covid-concerned passengers at ease with measures such as HEPA filtration, free sanitizing wipes at the door and deep cleaning after each flight.

Today, however, your plane might look more like it did in 2019 — or even dirtier.

As pandemic fears have eased, science on surface transmission has evolved and airlines cope with staffing shortages, some of those cleaning commitments have been relaxed. Still, experts say it remains safe to fly, especially as vaccinations and natural immunity have become more widespread.

The pandemic threw airlines' typical marketing campaigns out the window. Instead of advertising new routes, airlines started to compete on being "a leader in responding to the covid crisis," said Leonard Marcus, who launched the Aviation Public Health Initiative at the Harvard T.H. Chan School of Public Health in 2020.

The United States' largest carriers committed to installing hospital-grade HEPA filters throughout their fleets, providing hand sanitizer and wipes, regularly disinfecting high-touch surfaces, applying electrostatic disinfectant and deep cleaning aircraft every night.

Many of the airlines' cleaning measures involved disinfecting surfaces, and by the end of 2020 scientists had largely concluded that surface transmission of the coronavirus is rare.

"As more was learned about covid and transmission routes of covid, it was recognized that some of that deep cleaning was overkill," Marcus said.

And as more passengers have returned to the skies, certain measures airlines advertised in 2020 — such as deep cleaning aircraft between every flight — are no longer operationally possible, said Shashank Nigam, the CEO of SimpliFlying and author of "Soar," a book on airline branding.

One measure that has stuck around is air filtration. The United States' four largest carriers — American, United, Delta and Southwest — all continue to use hospital-grade filtration systems on their planes that replace air every few minutes. Many airports employ MERV filters in the terminals, one step below HEPA, and Delta has installed MERV filters in its jet bridges, according to a spokesman.

American and Delta representatives said the airlines continue to provide sanitizer and disinfect high-touch surfaces on the aircraft before every flight including seat belts, tray tables and arm rests, galleys and lavatories. They no longer apply an antimicrobial spray they used earlier in the pandemic; Delta said this decision was guided by the Centers for Disease Control and Prevention's determination that the risk of surface transmission is low.

United and Southwest continue to use an antimicrobial spray at regular intervals. A United spokesman said the airline also uses UV-C light to disinfect the flight deck and maintains a full-time medical director on staff. Southwest's website says its aircraft are deep cleaned for more than six hours each night.

Beyond the relaxation of some pandemic cleaning protocols, airlines are also dealing with severe staffing shortages that have strained cleaning staff amid soaring demand.

Nigam and Marcus said the precautions individual travelers take - such —s wearing a high-quality mask — remain the most important factors in staying safe while in the air.