DOJ Sues to Stop JetBlue's Purchase of Spirit

JetBlue is facing an antitrust lawsuit from the DOJ regarding its $3.8 billion takeover of Spirit Airlines. The DOJ alleges that the merger would increase ticket prices and reduce options for travelers. The Department of Transportation is also expected to block the transfer of Spirit's operating certificate. Despite regulatory challenges, if the merger succeeds, JetBlue would become the fifth-largest US carrier, potentially gaining more pricing power. The market reacted with Spirit shares dropping and JetBlue shares slightly increasing.

What historical context is provided regarding the Department of Transportation's authority to block certificate transfers?

What position would JetBlue hold among US carriers if the merger with Spirit is successful?