Avis is offering up to 9,999 Air Canada Aeroplan miles for rentals through March 31, but the bonus is somewhat limited in usability… not least of which because it’s just for my readers in or visiting Canada.  In addition..

First, it requires a 5-day rental or longer.

And second the higher mileage bonuses are applicable to higher car classes, smaller cars mean fewer miles.

Vehicle	Car Group	Bonus Miles	Coupon #
Sub-compact / Compact	A or B	2,500	MCAA037
Mid-size to Full-size	C, D, E	5,000	MCAA038
Premium, SUV, Minivan	F, G, H, V, W	7,500	MCAA039
Premium SUV	Z	9,999	MCAA040

The coupon code above generates the mileage bonus but per the terms and conditions of the offer must be used in conjunction with discount code (AWD#) H660500, which auto-populated when you click the ‘make a reservation’ link on the website for the offer.