Flying Slow.....

That's a relative term.

But if you are looking for an airplane that is capable of flying in the 4-10 mph. Electric Slowflyers would fit the bill

GWS ditributed by horizon makes a Tigermoth that stalls at 4mph
does 7mph in striaght level flight and about 10mph in a dive anything faster and the wings tend to fold.

This type of airplane might be for you. BTW the also fly indoors and can be flown in the average size backyard