Before Singapore Airlines’ flight attendants graduate to fly with guests, their rigorous, 15-week training program includes unbreakable grooming rules.

Among them: each ‘Singapore Girl’ – as the female cabin crew have been known since 1972 – is told on the first day of flight school which of five approved hairstyles suits her best: The pixie, the bob, the bun, the french twist and the french plait.

They are also instructed which make-up and nail polish colours they must wear.

“It’s about making the girl as attractive as possible, and her flaws less visible,” Amy Ling, the airline’s grooming consultant, told Traveller in September 2017.

“We don’t want them to look like a mother-in-law, hiding under an unsuitable hairstyle.”

The prescribed approach of Singapore Airlines is in stark contrast to that of Virgin Atlantic. It announced on Monday its cabin crew no longer has to wear make-up, including the signature red lipstick which has become a major part of its visual identity.

It also decreed pants will now be part of female flight attendants’ standard uniform.

For an airline which has, since its 1984 launch, based visual branding around sex appeal, the image decision is “a significant change”, Virgin Atlantic admitted.

Mark Anderson, the airline’s executive vice-president (customer), said the flexible approach to grooming would “provide our team with more choice on how they want to express themselves at work”.

So what are the cabin crew grooming guidelines of other airlines?

Since its ‘Blue’ days, Virgin Australia has given its female cabin crew the option to wear pants, but it isn’t necessarily following its international counterpart in relaxing make-up requirements.

“We are currently looking at our uniform ‘look book’ so we can keep up with the times and maintain a modern aesthetic for our crew,” a spokesperson told The New Daily.

“We want our female cabin crew to be as comfortable as possible in themselves and while on board, considering the amount of time they spend travelling.”

A Qantas spokesperson told The New Daily its female flight attendants can wear pants without special request, and “they do have to wear make-up as part of the uniform”.

Tigerair’s existing cabin crew make-up and grooming standards are similar to those of Virgin and Qantas, although it is an issue that the airline constantly reviews, based on current trends.

International airlines base branding and in-flight glamour as much around highly polished staff as they do aircraft innovation and safety.

A Thai Airways spokesperson told The New Daily the airline’s grooming policy means “make-up is part of the uniform. The look is very, very done”.

Hair and make-up tutorials are “absolutely” part of cabin crew training, and “I don’t see the day when they don’t wear make-up, to be honest”, said the spokesperson.

“The Thai Airways image is feminine, glamorous. But the look varies across age groups. The older staff prefer a more traditional style, and the younger ones tend to be a bit more Insta-ready.”

Thai Airways’ rigid policies extend beyond women’s grooming. Men must have their hair cut every three weeks and fingernails can be no longer than 2 millimetres.

Female cabin crew applicants must be under 26 and have never been married.

British Airways requires its female crew to at least wear lipstick and blusher and, according to 2015 uniform guidelines, “groom and maintain” their eyebrows and conceal “obvious blemishes”.

Qatar Airways cabin crew have their make-up (eyes, lips, nails and skin) checked before every flight by a supervisor. The carrier’s rules have spawned a number of online make-up tutorials:

Will Virgin Atlantic’s decision – which could lead the way for other carriers – change its brand identity?

“No make-up is not an issue, and I feel this is the airline’s way to move with the times,” stylist and author Trish Murray told The New Daily.

“Wearing make-up or not wearing make-up does not make me feel less or more safe while I fly. But presentation should, and still will be, a high priority – neat hair, good oral hygiene, nil body odour, clean hands.

“First impressions count and the ‘brand’ knows that. For airlines, poor attention to detail is not up for negotiation in this line of work.”