Some of the answers are pretty sick.
"Just take her. Dont take no for an answer."
She is a tiny human being for fucks sake, not a piece of furniture.
The OP maintains a good relationship with the mother. Is one holiday really worth completely scewing that up? "Take her to court."? Really?
The baby is 11 months old, breastfed and spent first month of life in SCBU and probably the mums PFB. Its totallh, completely, 100% understandable that the mother cannot picture her daughter doing as far as over the seas.
OP, from what Ive read you understand her anxiety some what, as you yourself pointed them out.
Please rememeber she will not be doing this to 'be controlling.' Or to piss you off. It'll be becaus of the natural, understandable anxiety she has regarding her daughter. Her baby.
Its whole year away, things change a LOT when the baby becomes a toddler.
You dont sound like a bad person, I think what you are saying is fair, but I think the mothers feelings are 'fairer'.
And I know Im BU, but I have a nearly 2 yo and it wouldnt happen. However, I have a child thats still breast feeding, suffers great anxiety and has very serious health problems so my feelings may be skewed. I would have probably been more ok with it with my first born who was having weekends away with his dad by this age.