Question: Where is the head office of a Portuguese regional airline that is a subsidiary of TAP Portugal and operates scheduled international and domestic services from its bases at Lisbon Airport and Porto Airport on behalf of a Portuguese regional airline brand name for TAP Portugal which operate short- and medium-haul routes ?
Sentence (from "TAP Express"): White Airways, an airline owned by Omni Aviation, also operates regular flights for TAP Express using 9 ATR 72 turboprops.
Relevant evidence: No