If you have ever had the notion of writing a story, fiction or possibly your auto-biography, this would be a very good opportunity to start your book.
I would just jump at the chance to be able to sit and read and not have to do anything else.
You could look up recipes online and find a bunch of stuff that you’ve been curious about making or tasting and start organizing your list.
You could go on one of those geneology sites and find out about your family tree.
If you have a lot of photos on your computer that need to be edited and sorted, that will take up quite a bit of time.
Get chatty with your seat mate and then write about the story later.