to work properly, you ll need lipo batterires. Ther will cost £25-75 a pack depending on size/capacity. Plus a charger. Id guess a running time of 4-5minutes, and be careful with these batteries. They have a reputation for not liking abuse, and catching fire. Dont recharge in your new merc SL55, then.
LiPo bateries are generally what's put into laptops and mobile phones these days, they can catch fire if you seriously overcharge them or physically damage them. Most of the stories on the web are the "RC aeromodeller who put their crashed 'plane in their SUV and then it caught fire" type of thing. clicky I'm sure no-one here is that dumb. /forums/images/graemlins/crazy.gif
sure, but the point is that for modelling these are going to be fast chargers, unless you happen to buy half a dozen batteries, or drive to a pond to play for 4 minutes.
With ref to this and the seaplane, you havent got a chance in hell of flying either of these for more than 10 seconds without training.