Grand Budapest Hotel reference - help me figure this out...

[auffahren]

My boyfriend is away on an unexpected trip abroad. Last night I text him "I love you" and he responded:

"And I love you. Auf fahren"

I asked him what he meant, but he said I had to figure it out.

Then today I text "I miss you" and he responded:

"And I miss you. Auf fahren!"

He has confirmed that it's a film reference from The Grand Budapest Hotel. But google isn't getting me anywhere. I know "Auf fahren" means "to go" or "to drive". But beyond that I've no idea what he's going on about! Can Mumsnet help?

I know the movie reasonably well, but I can't think of what the reference would be.

Oh! My husband got it immediately and thinks it's hilarious - let me see if I can find a clip.

I'm continuously refreshing waiting for an explanation! This has taken up far too much of my time today!

Can't find it. It's when Tilda Swinton is leaving the hotel, and she says through the car window that she loves Gustav and he says it back and then brusquely slaps the car and calls "Auf fahren!!" to the driver. It's v funny.

So is it a bit of a "I love you. Now bugger off"?

I've only seen the film once.

And it's abfahren! (11mins in)

Kind of!

Thank you! I'll watch it on Netflix later.

Abfahren-depart?
I need to re watch the film now

And thank you to your husband too.