Starting last fall, the Department of Homeland Security spent $464 million on a no-bid contract to buy 10 used airplanes from a firm in Northern Virginia. That was an enormous price tag, but the department said it had no time to consider other offers. The planes were needed urgently for deportation flights. But since then, the department has barely used this new fleet — for deportations, or anything else. The department’s Immigration and Customs Enforcement agency has long outsourced its deportation flights by chartering planes from private companies. It also uses military and Coast Guard aircraft. In a written statement,...