Converting a luxury jet gifted by Qatar to President Donald Trump into a replacement for Air Force One could potentially cost hundreds of millions of dollars and it could take up two years to install the necessary security equipment,

U.S. officials say it could be converted into a potential presidential aircraft to replace the 40 year old Air Force One. The Qatari government said a final decision hadn’t been made.

The Constitution bars federal officials from accepting gifts from foreign states without the consent of Congress.