FORT LAUDERDALE, FL - MAY 09:  A  Spirit Airlines plane takes off at the Fort Lauderdale-Hollywood International Airport on May 9, 2017 in Fort Lauderdale, Florida. Yesterday a chaotic scene erupted at the Spirit Airlines counter after flights were canceled which led to passengers getting irate and the police had to move in to restore order. Spirit blamed the delays on its pilots, who are negotiating for a new contract.  (Photo by Joe Raedle/Getty Images)
Why You May Feel More Emotional During A Flight
According to a 2011 survey by Virgin Atlantic, 55% of flyers become more emotional on flights. This may be due to the psychological effects of dehydration.
When a plane's cabin pressure is maintained at 6,000 to 8,000 feet above sea level, it can cause dehydration. As a result, the eyes well up with tears.
Travel expert Samantha Brown told CNN that when air conditions cause eye dryness, "the only way your eyes know how to create moisture is to cry."
Brown continued, "You have to be emotional to cry, [so] your body acclimates to the dryness and creates the tears, but has to create the emotion first to create the tears."
Cabin pressure also causes oxygen deficiency. As Dr. Robert L. Quigley told CNN, "One person might feel weepy, another sleepy — hypoxia affects people in different ways."