We are asking Ryanair to abandon the non-inclusive greeting "ladies and gentlemen" and replace it with inclusive forms: “people”, “travellers”, “passengers” or “guests”.

British Airways, EasyJet, Air Malta, Qantas, Japan Airlines, Delta, JetBlue, United and American Airlines have already made the needed change.

Why do we need neutral forms when greeting people? Out of respect. You wouldn't call your male colleague "a lady" or the other way around. Non-binary and intersexual people shouldn't be excluded either.

More explanation below, quoting
https://www.theguardian.com/commentisfree/2017/jul/14/tfl-scrapping-ladies-and-gentlemen-gender-public-toilets:
"[S]crapping ‘ladies and gentlemen’ isn’t about trying to abolish gender
Even biology isn’t binary, which is where intersex people come into the picture. Their physical attributes don’t fall into the rigid categories of “male” and “female”, and even within these categories there is so much variation. We all have varying amounts of “male” and “female” hormones floating around in us, for example, because biology is more complicated than just two options – as is life. Some intersex people strongly identify as men or women, but some do not. Why should anyone be excluded from public announcements?[...]
Doing away with the phrase “Ladies and gentlemen” isn’t going to change the world overnight, but our ideas about identity and how we see and treat people are made up of millions of everyday examples like this where there is simply no need to bring gender into the mix. It’s impossible to exist without hearing these cultural messages every day, from birth to death. So the push for a less gendered society isn’t so much about abolishing gender as curbing its more extreme manifestations – by gently chipping away at one pointlessly gendered aspect of modern life at a time."