The two largest airports in Denmark are Copenhagen Airport (located on Sealand 3.30 hour drive from Aarhus) and Billund Airport located 100 km (1.15 hour drive) south of Aarhus. Both airports have direct international flight connections to several major European cities and a large number of other destinations woldwide. Billund Airport is probably the best and easiest way to reach Aarhus.
Alternatively, Aalborg Airport is located 130 km (1.30 hour drive) north of Aarhus. Aalborg is a small airport, but well connected to several major European cities. Esbjerg Airport located 157 km (2 hour drive) south west of Aarhus and Aarhus Airport/Tirstrup located 40 km (35 min drive) north east of Aarhus are good alternatives, but both Esbjerg and Aarhus are small airports with fewer connections.