Kelly Dehn just endured a nightmare flight on Northwest Airlines. It wasn’t that her four-hour trip from Minneapolis to Orange County, Calif., lasted an extra hour because the aircraft had to be de-iced. It wasn’t even that she was three months pregnant. It was her mysterious seatmate.

From the beginning, my husband and I noticed a smell that appeared to be some sort of passed gas. These passed-gas emissions occurred every few seconds for the duration of the flight. We tried to identify its source. It seemed like someone was regularly passing gas or that someone with a full colostomy bag was sitting in near us. However, it did not smell human because it was very sulfur-like. We tried to adjust the fan jets on us, but it did little to overcome the smell. Soon we both developed headaches. As I have allergies (dust, cats, and dogs), my headache became a migraine headache. I thought it was due to the dust on the plane. Neither my husband nor I had ever seen such a cloud of dust as was circulating in the plane when the sun streamed in. It was like the cabin cleaners’ vacuums had no filters and just re-emitted the dust back into the air and onto the upholstery. I had difficulty breathing due to my allergies and the severe pain I was in. I tried to help alleviate it by drinking a lot of water. At some point toward the end of the flight, I used the bathroom. When I returned, I tripped over the sweatshirt stuffed under the seat in front of my aisle-seated neighbor, revealing a cat cage! The smell must have been the cat’s diarrhea.

Dehn was furious. Northwest had made no attempt to notify her she’d be sitting next to a cat. “This could have developed into an asthma attack or something else very serious,” she told me.

Because of Northwest allowing cats without warning other passengers, I lost more than 15 percent of my vacation suffering the effect. I don’t understand how this could be considered legal or even moral. I believe we should receive compensation from the airline for this problem. I also believe that laws should be changed to protect people from severe and common allergens such as cats.

Northwest’s contract of carriage is silent on the issue of pets and passengers. And to be honest, I wouldn’t expect it to address that kind of situation. This is more a question of airline policy, and it probably wouldn’t be published anywhere.

Dehn sent a letter to Northwest, requesting unspecified compensation. It replied with a letter saying that “regrettably, we cannot guarantee pet-free flights,” but that it does its best to ensure passengers are safe. It assured her that her comments would be shared with the appropriate people and offered her and her husband 4,000 miles each for the trouble.

Is that enough? No, says Dehn. “I couldn’t believe it,” she wrote to me in an email. “Four thousand miles?”

I agree that 4,000 miles isn’t a lot. But Dehn’s original letter, from which I excerpted earlier, didn’t offer any details about what kind of compensation she expected.

Northwest gets to punt this one to Delta, now that the two airlines have merged. An appeal to its new parent company might help, but I suspect the airline will regard 4,000 miles as plenty of compensation. In fact, it may view the miles as excessively generous in light of its recent billion-dollar loss.

Oddly, I think Delta might side with the passengers that pay the higher fare on this issue. In other words, it may support the cat.