Delta Air Lines is holding firm on its commitment to end a year-long middle seat block despite a newly released report from the Centers for Disease Control and Prevention that recommends keeping middle seats open to reduce the spread of COVID-19.

CEO Ed Bastian appeared on CNBC's "Squawk on the Street" Thursday morning and criticized the report's shortcoming when asked, saying: "Our experts tell us that with vaccination rates where they're at and demand being as strong as it is it's absolutely safe to sit in that middle seat."

Guiding Delta's decision, according to Bastian, are experts from the Mayo Clinic, Emory University, and Delta Chief Health Officer Dr. Henry Ting, formerly of the Mayo Clinic. The airline deferred to trade organization Airlines for America when asked for comment on the CDC report.

"Since the onset of this crisis, US airlines have relied on science, research, and data to help guide decisions as they continuously reevaluate and update their processes and procedures," a spokesperson for the organization said in a statement to Insider. "Multiple scientific studies confirm that the layers of protection significantly reduce risk, and research continues to demonstrate that the risk of transmission onboard aircraft is very low. "

Henry Harteveldt, an industry analyst and cofounder of Atmosphere Research Group, told Insider that the CDC study and its release were flawed for multiple reasons, chiefly because it doesn't take into account the new realities of travel. Researchers ran the trials in 2017 using maskless mannequins while masks are now mandatory in airplanes under federal law.

Harteveldt and airlines instead point to more recent studies, including one by the US Department of Defense where masked mannequins were tested onboard a United Airlines wide-body aircraft. Airlines similarly tout a Harvard T.H. Chan School of Public Health study that declares the risk of air travel to be "below that of other routine activities during the pandemic, such as grocery shopping or eating out" when precautions are taken.

Both support the claims by airlines that flying is safe thanks to measures like mask-wearing and the use of high-efficiency particulate air filters, or HEPA filters, regardless of whether seats are blocked. Harteveldt noted, however, that the Harvard study was funded by the airline industry while the DOD study was not.

Delta was an early and ardent adopter of the seat-blocking policy and kept seats blocked the longest of any major US airline, most of which started filling planes in late 2020. The policy cost Delta up to $150 million in potential revenue in March but even still, the month was successful as the airline saw positive daily cash flow thanks to a surge in travelers.

"Thanks to the incredible efforts of our people, we achieved positive daily cash generation in the month of March, a remarkable accomplishment considering our middle seat block and the low level of demand for business and international travel," Bastian said in an earnings statement, adding that he expects the airline to be profitable once more in September.

Come May 1, however, the American traveling public will not have an option to travel on a major commercial airline where middle seats are blocked.