Once, on take off from Gatwick, whilst the aeroplane was climbing most passengers on board felt that the plane was suddenly dropping backwards. I know it couldn't possibly have been doing this. In fact the only part of flying I hate are the take-offs, where I unfortunately close my eyes, start hyperventilating and gripping on the seat arms until it levels out, but I didn't seem to notice it. A lot of passengers did and some got quite panicky with the person next to me gripped my arm. Could the plane have hit some turbulance on its ascent, or do you think some people felt it was dropping when in fact it wasn't?
Welcome to the new network, this is our first day, first few hours in fact...and you'll be pleased to know that yours is the very first question asked.
In answer to your question; This is quite a common experience,it's caused by the engine power being reduced at the same time as the plane is reducing climb or levelling out. You'll find some help on this page of the wesite where there are some free podcasts. If you listen to number 15 that might explain things.