A Colorado woman is suing United Airlines for allegedly failing to protect her from an off-duty FedEx pilot she says touched her sexually three times during a flight from Hong Kong to San Francisco.

The claim, filed in Denver federal court on July 5, comes during an alarming rise in sexual assaults on flights under the jurisdiction of U.S. authorities. The FBI recently revealed there has been a 66 percent increase in such reports received by the agency between 2014 and 2017.

“We’re not sure why," FBI Special Agent David Rodski told reporters last month.

The latest suit alleges that Tennessee resident Monte Wedl was served three or four vodka sodas and took a dose of Ambien before he began the harassment of his Row 8 neighbor in business class, plaintiff Anne Maureen Dowling, as she dozed off for the long, trans-Pacific flight on July 9, 2016.

"We can’t comment on this case because of pending litigation, but safety is our top priority and we’re always looking for more we can do to ensure the safety and security of the hundreds of thousands of people who fly United every day," United spokeswoman Erin Benson said via email.

Wedl was acquitted last year after the U.S. attorney in San Francisco filed a criminal assault case against him based on Dowling's allegations. NBC News did not receive immediate responses after reaching out to the plaintiff's attorney, Wedl, or his attorney in the Bay Area case.

A FedEx spokeswoman said, "Wedl has not flown for the company since we were first made aware of these allegations. He is no longer an employee."

The Denver lawsuit states that the first red flag on the 2016 flight was when "Wedl got out of his seat and approached United’s flight attendant ... and told her that he had been away from home for two months, he missed his wife, and he is horny."

Wedl was told to return to his seat, and he did, the suit claims. But, after dozing off, "Dowling awoke to find Wedl’s hand on the back of her leg near her buttock."

The plaintiff shooed him off, the claim states, but she awoke again to find "Wedl’s hand rubbing her thigh, grabbing her butt, and attempting to reach into her pants. She cried 'stop' and he withdrew his hand from her body. She asked him what he was doing, and he creepily smiled at her in response."

Dowling went back to sleep again, only to have to fend Wedl off a third time because he was allegedly running his hand up her thigh, rubbed her crotch through her clothes and masturbated under a blanket, the suit alleges.

"Dowling shot out of her seat in shock when she realized what was happening and told Wedl to stop," the suit states.

As she gathered her things to move he said something like, "I think you're horny and I'm horny too," the suit claims.

The plaintiff asked a flight attended for a new seat assignment, but the United employee "suggested" that Dowling return to her seat and talk to Wedl, the suit alleges.

Dowling took the matter to the head flight attendant, who assigned her to a new seat in the same row but farther away.

"This is not okay, but I’m not shocked," the head flight attended is quoted as saying.

The suit claims Wedl made contact with Dowling one last time — to ask why she changed seats. "Dowling stated it was obviously because he had sexually assaulted her," the documented states.

The plaintiff sought medical care and counseling, had to take time off work, and suffered post traumatic stress disorder (PTSD) as a result of the assaults, the filing states. United exacerbated the situation by instructing Dowling to return to her seat and by serving excessive alcohol to Wedl, the suit alleges.

The lawsuit seeks unspecified damages above $75,000, the minimum for such a federal court claim, including costs related to medical care, counseling, time away from work, attorney's fees and future damages.

"Dowling suffered physical pain and suffering, shock, emotional distress, embarrassment, mortification, anxiety, anguish, loss ofenjoyment of life, loss of past and future income, loss of past and future medical expenses, and further injuries and damages as will be proven at trial," the filing claims.