Aachen Hauptbahnhof is a railway station, not an airport, so if you are searching for a lounge here expecting gates and airline services, the honest first step is a correction: the code XHJ refers to Aachen's main train station in western Germany, near the Belgian and Dutch borders, used for rail journeys and, in some interline arrangements, ground transport tied to airline tickets rather than an actual aviation terminal. There are no security checkpoints, no gates, and no airline lounges of any kind at this station.
Aachen itself is a genuine and historic city, known for its cathedral and its role as Charlemagne's former capital, and it sits within reach of two real German airports for travelers who do need to fly. Cologne Bonn Airport, roughly an hour east by road or rail, serves the wider region with a mix of low-cost and legacy carriers and airport-style amenities scaled to a mid-size hub. Dusseldorf Airport, a larger and busier international gateway a bit further north, handles considerably more long-haul and premium traffic, supporting a genuine range of airline and pay-in lounge options for travelers with the right ticket, status or membership.
Because Aachen has strong rail connections into both cities, travelers combining a stay here with an actual flight typically plan the journey as a train-to-airport transfer rather than expecting any airport-style service at the Hauptbahnhof itself. Confirm current train schedules and transfer times before booking a tight connection, since rail timetables between Aachen and either airport can shift with maintenance work or seasonal schedule changes.
For anyone whose trip involves both Aachen and an actual flight, the practical routing is straightforward: treat the Hauptbahnhof as your rail departure point, and plan any lounge visit around Cologne Bonn or Dusseldorf depending on which better matches your route, since neither lounge access nor any other airport amenity exists at the station itself.