What will be the output if I connect two 1.5 AA Alkaline batteries (3V) to a 3.3V Voltage regulator (LM1117)?
LM1117 is a Linenar regulator, this mean, Vin > Vout in any case. You can not "increase" the voltage. If you want to do so, you better use a boost regulator. But I'm not sure it will work for a such little amount extra voltage (I can be wrong).