Travelling abroad while potty trainign a 2yo and 4yo

[eversomuch]

Any advice? They will both wee in the potty and the 2yo will wee in the loo at home, but neither of them will go on any other toilets. Generally, they're in underpants all day (with lots of accidents) and nappies at night. We're looking at a 1.5hr tube journey, then a 2hr flight and short bus ride to our destination. Then four days out and about.

Should I plan for pull ups? (Will, of course, have lots of changes of clothes with us and we'll have access to a washing machine.)

Worried about causing them to regress and it's taken us 2 months just to get to this point.

In this situation I would seriously have a re think as to if they are actually ready, given your mention of lots of accidents. (Especially the younger). I may even cancel potty training and start again after my break.
If I decided to forge on regardless, then I think you need to be considerate of others and use pull ups. The tube (assuming London) has very few public toilets afaik, and none underground or actually on the trains. And there can be long periods on flights when seat belt sign is on, or a long wait until take off etc when everyone is confined to their seats. Unfair to risk wetting the seats.

I put pull ups over pants! They still feel wet, still would be better to use the loo or potty, but saves seats and stress if there's an accident. I do this for car journeys too.

I mean over their normal pants.