It depends on what you want from your career.
If it was me, I would look into the start up company. A few reason;
- It is something totally different
- Destinations you will never have been to, and possibly never would imagine having gone to
- Cost of living in Asia is about 50% less then Europe, so generally speaking, you would have a better quality of life in Asia.
- People are friendly
- You are entering a company that is very young, meaning you will be very senior in the company if they continue to expand
- You will still be flying and gaining hours
The downsides to the start up are fairly obvious, the main one being that it is possible it will go belly up.
Look into who is running the company, and the structure of the management. do some research into their past employment and organisations they headed to see if they were successful.
I have many friends working in airlines across the world, and many of them in Asia. They love it and a couple have made it clear they will never return to fly in Europe.
Like I say, it is all about what you want from your career and what type of person you are. If you like safe, never want to take a risk then stay in Europe.
Just think on these two statement;
"You never become a millionaire by working for someone else."
"Take a risk and it might pay dividends, play it say and don't make millions."