Many recipes (e.g. orange chicken) call for the chicken to be coated in flour, the beaten egg (whole, whole with a dash of milk or just the whites), coated again with flour and then deep fried. The flour can be plain flour, plain flour with cornstarch, cornstarch and potato starch etc.
I've had excellent results just coating the chicken with seasoned flour (or a flour mixture) and then deep frying after leaving it to air dry for 15 minutes. I have never had any problems with the flour coating coming off while it is cooking. Is this because the chicken breasts I use are particularly "wet" due to the water injected during processing or am I just fortunate that my chicken has not come out particularly dry inside?