You wrote:

"Alternatively add the parameter as a nodelist, you'll have to change it
something like <airlines><airline>alitalia</airline>.....
Then you can compare directly as you did initially."

I dont know how many options can I manage...
It depends from the nodelist results.

So I dont understand well How can I build a nodelist like
"<airlines><airline>alitalia</airline>" and compare it...

Could you give more explanation?

Thanks in advance.
Giancarlo