A flight instructor and her student, a U.S. Navy officer who was also a father-to-be, are presumed dead after their small plane plunged into a New Orleans lake, according to authorities and local reports.

Instructor Taylor Dickey and her student, Navy Lt. David Michael Jahn, took off in a Cessna 172 Skyhawk last Monday, but the aircraft disappeared from flight radar over Lake Pontchartrain, about four miles north of New Orleans Lakefront Airport, according to the United Cajun Navy. Coast Guard said its agency suspended operations Wednesday afternoon after crews searched by air and water for roughly 45 hours, covering more than 770 square miles.

"Our hearts go out to the families and loved ones impacted by this tragic situation," Cmdr. Michael Wurster, the Coast Guard Sector New Orleans search and rescue mission coordinator, said in a statement. "Suspending a search is one of the most difficult decisions we make, and it is done only after every effort has been made to locate those involved."

Michael Carastro, the owner of flight school Apollo Aviation that owned the plane, said during a press conference on Tuesday that no distress call was made, but the plane likely disintegrated on impact in a "very, very violent" manner.

He described the challenges of flying over water at night, especially in "marginal" weather, present a lot of challenges to the pilot. 

The United Cajun Navy said the group deployed boats, sonar teams, air support and K9 units amid harsh weather during the holiday search mission.

"This is how we spend our Thanksgiving weekend out here trying to bring closure to somebody else's family," Kevin Ratzman, the deputy instant commander for the United Cajun Navy, said. 

Carastro also expressed profound grief and noted that this was the first serious incident Apollo Aviation had experienced in its decades of operation.