Permission from Ex to travel to USA

[Pencilplant]

I've split up with my husband for over a year and I am traveling soon to the US with my parents for a holiday. Do I need to get a letter from him giving permission for them to travel with me? He is an alcoholic and very inconsistent about how he behaves with me. I've not met him take the kids abroad for obvious reasons so I'm sure he will make this difficult for me. So what do I do and do I need a letter?

Bump

I never asked my ex for permission, my son has his name too, not mine. I think other people have had trouble though, hopefully others can advise.

Thanks Buttered. X

Bump. Pencil there might be more traffic in the likes of chat thread maybe.