Small DC motor in parallel - what battery to use for powering the circuit
If those motors are 24000rpm you'll need to gear them WAY down to do anything useful.
Run them with nothing at all on the shaft and 2xAA batteries should last a good while. Check this now.
You haven't said, but I'm guessing you have put wheels or propellors on them ungeared, so they are practically stalled and draining your batteries fast. (Easy to hear the difference in speed)
Use those gears to gear them down about 5:1 for those propellors or 25:1 to run those wheels across the floor as a starting point.
To be more scientific about it you'd need a multimeter that can measure several amps of current, and measure the current both completely unloaded and with load .. you'll easily see the difference. A bit more information here...