Hi atlantabraves2000,

Regarding 1), you can reach Vueling from the US by calling them on (+34) 931 518 158.

Regarding 2), the city transit in Barcelona is great! The city has an Airport Shuttle service (Aerobus) that comes every 5 minutes and costs just 10 EUR for a round trip ticket to Plaça Espanya and Plaça Catalunya (the epicenter of the city). The metro system is very well connected and most lines pass through Plaça Catalunya.

If your wife is going to stay a few days in Barcelona and it's her first time, then I always recommend staying near Plaça Catalunya precisely because it is the epicenter of the city and the central transportation hub. It will make getting around Barcelona a lot easier for her, and it's sandwiched right between two must-see districts, Ciutat Vella (Old City) and Eixample.

Barcelona is a safe city, but she will need to be aware of pickpocketers. They are non-violent and non-confrontational, but very sneaky, so as long as she's aware of her surroundings at all time and not flaunting cash and valuables, she'll be fine.

Hope this helps.

Cheers,
Aleksandra