Is It A Bird ? ... Is It A Plane ?

I’m just surprised they make a costume of that type in that size.
I give her credit for wearing it :-)

'Off the peg' in the USA ?

Lol, I actually had to look up the meaning of that.
Yes, here on our side of the pond they have stuff for all sizes apparently. It’s probably an American thing with all our fast food, soda and sweets.
Howdy, from the U.S. :-)

And good day to you sir, from the UK
To be fair, we do have a problem in this country with ... how shall I put it ? .... Fatties ! :~)