Chair Airlines (GM, Zurich) began wet-leasing a B737-800 from its Polish parent Enter Air (E4, Warsaw Chopin) on July 21, 2021, under a previously announced summer-long capacity-boosting ACMI contract.

SP-ESE (msn 30688) has had the Enter Air logo replaced with Chair's but otherwise remains in the Polish carrier's livery. Enter Air ferried it from Antalya to Zurich on the morning of July 21 and operated its first revenue flight for the Swiss company to Skopje, on the evening of the same day.

Chair Airlines operates two A319-100s, the ch-aviation fleets module shows. The carrier's third unit of the type was damaged beyond repair during a maintenance mishap at Naples Capodichino in mid-2020, precipitating the need for wet-leased capacity for the peak season.

Enter Air owns a 49% stake in Chair Airlines. The Polish leisure carrier operates twenty-four B737-800s and two B737-8s. It has a further six B737-8s on firm order from Boeing.