The Swiss Federal Office of Civil Aviation (Bundesamt für Zivilluftfahrt - BAZL) has withdrawn the commercial licence from JU-Air (Dübendorf), at the same time theoretically permitting the operator to continue Ju-52 flights for club members.

"However, the JU-Air vintage aircraft remain on the ground for the time being, as various technical measures required by the BAZL have not yet been completely defined and implemented," the authority said in a statement.

If the carrier implements the necessary security measures ordered by BAZL after the August 2018 crash of one of its Ju-52s, it will be only permitted to carry passengers who have been members of the club for at least 30 days and have been informed of extra risks associated with flying historic aircraft.

"With this solution, BAZL aims to enable the continued operation even of large historic aircraft," the statement reads.

In November 2018, BAZL indefinitely grounded JU-Air's two remaining Ju-52s over maintenance oversight concerns. The authority said that at this point, there was no indication as to when the carrier could resume flights.