We will be traveling in Eastern Europe for the first time in April. Are the signs/directions in airports posted in English?

Eastern Europe is a big place - where are you going? What signs are you looking for? Gate #'s? Those are pretty obvious. Baggage claim? Follow the crowd, or look for signs with a picture of a suitcase. Taxi = universal word.

At larger airports - very often. Smaller ones - sometimes. But almost everywhere there are pictograms, such as a suitcase indicating baggage claim.

I don't think as airports as a place I need to read signs. It's all numbers or symbols, most often.

There will probably be some english in places - but I don't even look for the "words" in London or Dublin. A pictograph of a taxi will point you to the taxi rank. A train/trolly pictograph - to the metro or train station. An "i" usually indicates information desks. A drawing of a cash machine will point you to the ATM. A knife and fork - restaurants. etc etc.