If you wish to fly more than 5 flights in a one day period you either need to switch to lithiums which can be easily fast charged at the field or get a second airplane.
The thing about nimhs and nicads they need to be fully charged the night before going flying. In fact if I charge on a Friday to go fly on Saturday and for whatever reason do not go fly on Saturday then those batteries get cycled down and then recharged fully for Sunday. That is just my personal preference and comfort for flying when using nimh/nicads.
I am slowly converting over to lithiums.