Air New Zealand Air Points - Passport number required at time of online booking?

Quick question for you guys; Is the passport number a required field when booking through the on-line booking engine for flights to the UK? My mother is waiting for her passport application to be processed, but wants to book flights (for September) right now.

I haven't struck this before myself as I have always had a valid passport.

Thanks for the information!

We did it about a year ago when our passports were due to expire before our flights.

It allowed us to book, but reminded us it was our responsbility to ensure we had current passports for our trip.

So hopefully there won't be a problem, although in our case we did have passport numbers to enter in the fields.

That's not a mandatory field when you book and I also believe they have the ability to change your passport number at check in. If going via the states, you need to make sure esta is valid.

Great! Thanks for the info guys - most appreciated!