Hint - if you are reading this on May 1st, go two posts back for better discount. Although , I should admit, I dislike tango-only discounts...
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Book by May 3 with this promo code and save 5%

To get your exclusive discount, simply enter this promotion code when booking right here at aircanada.com:

Promotion code
CDASPRING5
About this offer:

Valid on Tango fares.
For travel between May 15 and June 26, 2013.
Book by May 3, 2013,
11:59 p.m. local time, from your city of departure.
Codeshares flights are excluded
This exceptional offer applies only to the following routes:

All Canada - All Canada