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,

Boeing has not officially confirmed any changes to the $3.9 billion fixed-price contract it signed during Trump’s first term. It has absorbed more than $2.5 billion in losses on the project.

Qatar’s royal family has offered a luxury Boeing 747 for Donald Trump’s use as president. Boeing already has a contract for two new 747s.