Source: p 238, With Good Reason, An Introduction to Informal Fallacies (2000 6 ed) by York U. Prof. S. Morris Engel. Disclosure: I do not benefit or gain from, and am in no wise connected to, Avis.
Present-day advertisements are subtle, but irrelevant appeals to sympathy persist, as in Avis Rent-a-Car's successful slogan: "We're number two."
Avis's argument appears a Valid (but Unsound) Deduction to me. So how is it an Appeal to Pity?
Premise 1: If Avis is #2, then Avis will improve to be #1.
Premise 2: If Avis is #1, then you should choose Avis.
Conclusion. 3: You should choose Avis.