If you want to visit remote Mongolia out of classic main tourist season on board of a good ranked carrier check out this awesome offer from Denmark based on Turkish AIrlines. (Member of a Star Alliance). At this moment you can book very cheap flights between Copenhagen and Ulaanbaatar already for €327. This is including all taxes as well as checked luggage. Flights are mostly available for winter schedule..Please check what is the weather like in these months before you book this deal…
You will find the cheapest flights from November 2018 to March 2019. (Except Xmass). Some cheap deals also in May 2019 however very limited. (Simply compare the cheapest travel dates directly at website of the airlines then compare the cheapest option via Skyscanner. Max stay 12 months and no further restrictions of this promotion. Please refer to below booking sample if interested in this offer.
Booking sample of cheap return flights from Copenhagen to Ulaanbaatar, Mongolia from €327! In this case you would depart from Denmark to Mongolia on 18th of March. Return from this remote and isolated country in Asia back to Europe on 30th of March 2019.