It's been barely a week since Brazilian aircraft maker Embraer ( ERJ -1.79% ) announced that it's getting into the air taxi business, with its Eve Urban Air Mobility Solutions subsidiary striking a deal to sell 200 electric vertical takeoff and landing (eVTOL) aircraft to helicopter travel services provider Halo. But on Thursday morning, Embraer shareholders are reaping a windfall benefit from that deal. Its stock was up by 13.7% as of 11:30 a.m. EDT on news that it may spin off the Eve subsidiary in a deal with a SPAC.