Riyadh Air and Saudia will purchase 78 Boeing 787 Dreamliner planes under agreements announced Tuesday in a giant order that underlines Saudi Arabia's goal to remake itself as a global aviation hub. - Vision for Riyadh - Under the particulars, Riyadh Air agreed to purchase 39 Dreamliners, with options for 33 more jets, while Saudia will buy 39 Dreamliners with options for 10 more.