Buckle up, summer travelers. The airlines are planning for a big increase in ticket sales as vaccines become available to everyone. Specifically, as the weather gets warmer, the travel industry expects summer travel to hit pre-pandemic levels.

Airlines were hit hard as the pandemic began and air travel was shut down, then restricted as mitigation measures for the virus took effect. Air travel is slowly coming back now and airlines want to be prepared for what they hope will be a busy summer travel season. For example, American Airlines reports first-quarter seating capacity fell 43% compared to 2019. The airline is predicting it will increase up to 90% domestically and 80% internationally in warmer months. It is adding 150 new routes. The new routes are both domestic and international, and include Mexico and the Caribbean.

Delta Airlines is planning to reopen middle seats in May. United Airlines is adding 24 new routes by Memorial Day.

The CDC quickly stepped forward to try to squash any plans to open up middle seating on planes. Not so fast, there’s still a pandemic going on. The CDC released a study from Kansas State University that determines that vacant middle seats on planes reduce the risk of exposure to COVID-19. The airlines may be jumping at the chance to pack paying customers in like sardines again but the CDC is throwing cold water on the idea.

With vaccinations widely available soon and major attractions slowly reopening, it’s just a matter of time before families are planning a few days at Disney World. Grandparents will be planning visits to see the grandchildren they’ve been apart from for over a year. Travelers are more than ready for a change of scenery and looking for good deals on air travel. The CDC warns that it is not the time to get carried away and load in as many flyers as possible on planes. Not yet, anyway.

“Throughout the pandemic, our trademark has been to build a schedule based on what customers tell us they want and need,” Brian Znotins, American’s vice president of network planning, said in a news release. “And today, they are telling us they’re eager to get back to travel.”

With international travel still depressed, American plans to use some of its Boeing 777s widebody aircraft on domestic flights to New York and Los Angeles from its Miami hub. American and competitors like United and Delta have added flights to destinations with outdoor attractions like beaches and mountains, as travelers seek vacations where they can physical distance from others.

As airlines lift on-board capacity limits, the CDC released the study but one factor was not taken into consideration – the use of face masks. The study was made before the COVID-19 pandemic and before face masks were mandatory in air travel.

Keeping middle seats open on aircraft could reduce passengers’ exposure to the virus that causes Covid-19 by more than half, according to a new study published Wednesday.

Researchers from the Centers for Disease Control and Prevention and the Kansas State University found in laboratory modeling that passengers’ exposure to SARS-CoV-2, which causes Covid-19, on wide-body and narrow-body planes could be reduced between 23% and 57% if airlines leave middle seats open — even if they aren’t wearing masks.

The researchers’ study did not examine mask-wearing on flights, which became an airline and federal government policy during the pandemic.

However, they cited a New Zealand case study that said “some virus aerosol is emitted from an infectious masked passenger, such that distancing could still be useful.”

They used a surrogate virus to stand in for airborne SARS-CoV-2.

Airlines point to compliance with strict cleaning procedures and new air filtration systems implemented to protect air travelers during the pandemic.

The study comes after airlines have spent much of the last year touting stepped-up cleaning procedures and onboard filtration to calm travelers worried about flying during the pandemic. Travel demand has since rebounded somewhat as more of the public is vaccinated against Covid-19.

U.S. airlines including JetBlue Airways and Southwest Airlines capped capacity on board their planes earlier in the pandemic but have since done away with the policy, citing hospital-grade filtration and other safety measures as limiting the risk of exposure. Delta Air Lines plans to stop blocking middle seats next month, the last U.S. airline to make the change. It paused its capacity caps during Easter weekend, though, during a staffing shortage that contributed to dozens of flight cancellations.

The argument over selling middle seats is coming late, though. Delta is the only airline to still restrict middle seats in economy class. The airline plans to open the seats up in May. Southwest Airlines, by comparison, began selling middle seats last December. The airlines are ready to get back to more normal operations. The report doesn’t say what the reduction of exposure is for air travelers if the middle seats are used while all passengers abide by the mask mandate.

The research, done in conjunction with Kansas State University, found a 23% to 57% reduction in exposure to “viable” virus particles when middle seats are vacant.

The conclusion: “Physical distancing of airplane passengers, including through policies such as middle seat vacancy, could provide additional reductions in risk for exposure to SARS-CoV-2 on aircraft.”

One emergency room physician called the report a “bombshell” dropped by the CDC on the travel industry.

“The CDC just dropped a bombshell on the airline industry,” said Robert Glatter, an emergency room physician at Lenox Hill Hospital in New York. “That’s really what this report is.”

Airlines deferred comment on the CDC study to their trade group, Airlines for America.

The group’s statement did not address the study but reiterated that airlines have a host of measures to prevent virus transmission on planes, including hospital-grade ventilation systems, strict face mask requirements, preflight health forms and intensified cleaning of planes.

People are ready to get back to their lives, which includes traveling. With common-sense precautions, while the pandemic is still with us, a vaccinated majority of travelers will be willing to board full flights again. I can’t imagine anyone is excited about being stuck with a middle seat, though. Maybe families with children who can fit more comfortably in the seat will be happy over the decision.