The suggested standard would create an option of "unspecified" or "undisclosed" when booking tickets, in addition to "male" or "female".
"As part of our commitment to inclusion, we want to ensure all of our customers feel comfortable and welcome no matter how they self-identify, which is why we will begin offering our customers the ability to select the gender with which they most closely identify during the booking process," United Airlines said in a statement to USA Today.
The airline said changes would be made in the coming weeks and added that "customers will be able to identify themselves as M(ale), F(emale), U(undisclosed), or X(unspecified), corresponding to what is indicated on their passports or ID. ... Customers who do not identify with a gender will have the option of selecting 'Mx.' as a title."
Currently when booking online with Air New Zealand, gender is not a required field, but only male and female are listed as options. Passengers are required to include a title on their bookings, most of which are gendered.
A spokeswoman for the airline said "diversity and inclusion" were "hugely important" to the organisation and they hoped to implement similar measures as the US airlines.
"Our Chief Executive Officer, Board and Executive team are big supporters of gender diversity, and they are supported by a dedicated Diversity & Inclusion Manager and leaders who sit within business units.
"We're proud to have recently gained Rainbow Tick accreditation, which deems our workplace a safe, welcoming and inclusive place for people of diverse gender identity and sexual orientations."
Jetstar does not ask for a passenger's gender when booking a ticket, but does require a title. The airline has been approached for comment.
Air New Zealand's plans could put their booking practices in line with existing passport options for Kiwi travellers.
The New Zealand passport allows people to state their gender as male, female or "X" (indeterminate/unspecified), without the need to change their birth certificates or citizenship records.
Ahi Wi-Hongi, the national coordinator for Gender Minorities Aotearoa, said they welcomed changes to Air New Zealand's booking process.
The organisation offers cross-cultural services and information for takataapui, transgender, and intersex populations in New Zealand.
"We think it's good for Air New Zealand to add more gender options. It makes sense because we have infrastructure for that in terms of the passport," Wi-Hongi said.
"It's out of sync at the moment, so it would be good to line that up with the process for passports."
Travelling could already be a very stressful situation for transgender, non-binary and intersex people, who "often feel like they are really standing out" at airports, they said.
"Some people have problems travelling with X on their passports if the airlines don't accept X as a legitimate gender marker, because it's automated in the system.
"They might have to end up putting M or F instead of X, but then it doesn't match the passport, so it can be quite stressful even if the travel is allowed to go ahead."
Wi-Hongi said the simplest solution would be for airlines to offer an X option when booking, alongside M and F - which could be used by both people with a non-binary gender and those who didn't want to specify their gender.
