This Travelodge hotel is in front of La Fira 2 (Barcelona's new exhibition & trade fair area). There is no bus or metro stop nearby. The only way to reach this place is the taxi.
If the purpose of your visit is not business in the area of Hospitalet or a trade fair, honestly that's not the place.
If the purpose of being there is just being "close" to the airport, that really makes no sense, as you'll be (just a bit) closer to the airport but your transport options will be limited to taxis.
Cheap, functional accommodation out of trade fairs periods