"You could feel the tension in the air as passengers who had been stranded since Sunday began to realize today might not be their lucky day," Heather Mikesell told ABC News. "When a couple of passengers tried to cut the line, those who were patiently waiting their turn revolted."
In Cleveland, police officers were called to at least one gate to maintain order.
For many travelers, the airlines' treatment of them has become the final straw in a frustrating few days.
Terry Loerch has been trying to get from Maryland to his home in San Diego but has found that JetBlue canceled his trip and that of others traveling to San Diego. The airline's answer to him: Wait until Jan. 3 to get home.
"In all my decades of flying, I have never been pushed from a flight I scheduled, paid for in advance and planned my trip around," Loerch said. "Their inconsideration and poor business sense is alarming for this day and age.
"Their service was relevant to buying a burger as opposed to a flight, and their solution to send me on an alternate flight six days later preposterous and the worst business model-solution I can imagine."
Delta lost Matt Blaszka's bag on his way out. Now, for his return, he couldn't check in because the airline's website was down for a large part of Monday night.
"The customer service has been poor," he said.
The airlines acknowledge that the phone lines have been jammed but say the situation is improving.
"Call volume has been very high due to two days of airport closures and flight cancellations," said Allison Steinberg, a JetBlue spokeswoman. "As we resume service and begin a return to more normal operations, the call volume has been decreasing and the hold times have been lessening. We're doing everything we can to reaccommodate customers as quickly and efficiently as possible."
ABC News' Leezel Tanglao, Daisha Riley and Sarah Kunin contributed to this report.