President Donald Trump really wants to fly on an upgraded Air Force One — but making that happen could depend on whether he’s willing to cut corners with security.

Air Force Secretary Troy Meink told lawmakers on Thursday that it will “probably” cost the Air Force less than $400 million to retrofit a luxury Qatari plane that President Donald Trump has said he is getting from the Qataris as a gift to use as the new Air Force One.

Retail investors seem to have spotted an opportunity in the sudden feud between U.S. President Donald Trump and his former ally, Tesla CEO Elon Musk, scooping up shares of the electric car maker as they tumbled on the acrimonious standoff.