Classification of the organisms based on their method of locomotion would be flagella, pili or gliding. The structure that offers the highest motility of those 3 would be flagella.
An organism with flagella could be further classified on the number of flagella such as: atrichous(no flagella), monotrichous(1 flagella), amphitrichous(flagella on both side), lophotrichous(many flagella on one end), peritrichous(flagella all around the membrane)