how to get from berlin to prague?

Czech Airlines has direct flights (one hour).

Flying is always the fastest way. But there are so many marvels and gems between Berlin and Prague, like Wittenberg where Martin Luther posted his theseses and started the protestant religion or Dresden, a city filled with sights... or the Elbe canyon in Swiss Saxony which is quite unique...

I try to avoid the planes unless the distance is far enough to make up for the normal airport hassle. By train, you can go direct from Berlin to Prague in 4.5 hours - and if you want, hop off the train in Dresden for a nice break. here is an itinerary for the direct route

Berlin Hbf (tief)- 8:46
Dresden Hbf - 11:09
Praha-Holesovice - 13:21

Since you asked for the fastest way, I gave it to you in my previous post. However, I agree with the others that taking the train is a much better way to go. Discount fares booked at www.bahn.de can be as low as €29. (No stopovers allowed at that price.) Click on "Internat. Guests" to view the site in English. Enter Praha as your arrival city.