A friend of Ms McMuffin, Molly McIsaac, posted about the incident on May 18 on Facebook.
Alongside a front and back picture of the outfit in question, Ms McIsaac wrote, "This is what she was wearing last week when JetBlue told her she was dressed inappropriately and couldn't board the flight from Boston to Seattle she had paid for.
"She was connecting in Boston from NYC, also a JetBlue flight - which had no issues with the way she was dressed."
Ms Isaac said that her friend was forced to go to another terminal to "buy a pair of women's sleep shorts in XL for 'proper coverage'".
The post added that although the company has apologised for the incident and refunded her for the flight and the additional clothing Ms McMuffin was forced to buy, the pilot did not apologise and there was no "explanation for their behaviour".
Since the post appeared on May 25, it's had over 1600 shares but the reaction has been mixed.
Edie Gutierrez commented, "Oh, get a life Miss McMuffin. You think you are cute but actually you are so lacking in self respect. They look like your underwear anyway, and not classy at all."
Jas Kat Wong wrote, "You people who are saying she's wearing underwear are way too conservative. I'm glad that I live in a city that I can walk around in underwear and not have it questioned. She's not naked."
Ms McMuffin told Kiro 7, "I've seen people online that say this looks like underwear because of the shape but I have walked around in outfits like that before."
JetBlue's Contract of Carriage (the terms and conditions of boarding the flight) stipulates that they can remove anyone "whose clothing is lewd, obscene, or patently offensive".
A JetBlue spokesman told MailOnline Travel: 'The gate and onboard crew discussed the customer's clothing and determined that the burlesque shorts may offend other families on the flight.
'While the customer was not denied boarding, the crewmembers politely asked if she could change. The customer agreed and continued on the flight without interruption.
"We support our crewmembers' discretion to make these difficult decisions, and we decided to reimburse the customer for the cost of the new shorts and offered a credit for future flight as a good will gesture."