The students and teachers from Joseph Konig School were returning home from a Spanish language exchange program aboard the Germanwings Airbus A320 when it crashed.
The plane was traveling from Barcelona, Spain, to Dusseldorf, Germany, when it suddenly began a rapid descent from its cruising altitude at 38,000 feet. It plunged 32,000 feet in eight minutes, according to Germanwings. When the plane was at 6,000 feet, it lost contact with air traffic control.
The plane was carrying 144 passengers, including two babies, and six crew members, Germanwings CEO Thomas Winkelmann said at a news conference Tuesday.
The high school held a makeshift memorial in its gym Wednesday. Many carried candles and signs as they mourned their peers. One mourner carried a sign that said, "Yesterday we were many. Today we are alone."
Ina Grajestiki, a violin teacher at Joesph Konig, told ABC News, "I don't know how to work today. ... I cannot believe this, that it's happened."
Police helicopter searches of the Germanwings Airbus crash site resumed Wednesday morning.