Japan's female flight attendants are reportedly using prostitution to supplement their increasingly low wages.

Several cash-strapped air stewardesses are allegedly improving their financial situation by regularly sleeping with pilots for more money, unidentified female cabin crew members shockingly revealed to Japan's Shukan Post, adding that staff can charge between $450 and $650 to spend 90 minutes with a client.

"Stewardesses who are willing to do it with a pilot pass their number to a senior stewardess who is effectively a female pimp," one air hostess said. "Other stewardesses outsource their services through companies, some of which specialize in offering air hostesses."

During pre-flight briefing checks, the stewardesses line up before the pilot and co-pilot, who then allegedly proceed to hint signals with their fingers, UK MailOnline reported.

"There is also a system where the pilots use hand signals to tell the hostesses they are interested, and how much they will pay," she said, adding that four digits raised to the nose indicates an offer of 40,000 yen, around$340, for an overnight stay at a hotel.

According to another stewardess, those under 30 are able to charge the highest amounts for their services.

"We have an expiration date," said a 29-year-old, who is also involved in an escort service that specializes in offering clients with stewardesses.

Every year, tens of thousands of young women apply for flight attendant positions, also known as a soochoowadesu, with the country's major airlines since it is considered to be a dream job for a majority of Japanese women.

But in reality the job entails poor pay and long hours, with salaries for Japan's flight attendants experiencing a significant slump over the past decade, from $42,000 a year in 2004 to just $33,000 in 2013, according to the Ministry of Health, Labor and Welfare.

The "prostitution circle" began several years ago, a 30-year-old attendant, who joined an airline in 2007, told the Shukan Post. But the operation was temporarily closed down after upper management was alerted and the ringleader got terminated.

"But since the girls in the circle at the time are still employed at the company, I'm sure it still goes on even now," said the attendant. 

Aside from prostitution, air stewardesses also take up part-time work as party companions or bar hostesses in Tokyo's ritzy Ginza district, according to the magazine.