The buses are run by KTEL but the company’s website is not tourist friendly at all. It’s impossible to find any timetable online and if you want to call them, you have to speak Greek (and pay a hefty fee for the call).
Getting to the bus station from the airport is probably the easiest thing is Thessaloniki, as public bus line 78 (or 78N at night) starts at the airport and ends at the bus station. So just hop on and enjoy the ride! If you are not going to the bus station from the airport, other lines that can get you there are: 1, 8, 12, 45, 80, 81, 82A, 82B, 82E, 82K, 89A, 89B.
At the bus station you should get a bus to Trikala, which is the big city near Kalampaka and Meteora. Once you get to Trikala you can catch a bus to Kalampaka.
There aren’t any direct trains between Thessaloniki and Kalampaka / Meteora. You need to change trains in Larissa.
In order to get a train to Meteora, you have to get to New Railway Station, or “Neos Sidirodromikos Stathmos” at Thessaloniki. Now, Thessaloniki does not yet have a Metro, so your options are getting a taxi or getting a public bus to the station.
If you are getting to Thessaloniki by plane, then you can get into bus line 78 (or 78N at night) and hop off at the railway station. This is probably the easiest way to get to the station.
Other bus lines that stop at the railway station are: 2, 3, 8, 9, 10, 14, 17, 19, 37, 38, 40, 51, 52, 54, 56, 64. Take care in getting the bus that goes to the railway station and not the other way around. You can see at each bus stop the lines it serves and find the nearest one that gets you to the station.
At the Train station, you can choose one of the trains below to reach Kalampaka, which is the city below Meteora. Kalampaka is a terminal station, meaning that if you get on a direct train you won’t have to worry about getting off at the right station. It will be the last one!
Please take into consideration that some train routes change to Paleofarsalos station. You should be aware if your train is a direct one or not.
By car renting a car is the best option if you don’t like to change trains or worry about bus departures.
The driving distance between Thessaloniki and Meteora is 216 km and it takes about 2.5 hours. Part of the drive is on E90 (route 15) which is a partial toll road.