What exactly is IKK
 

I have seen it a million times and read the definition, but for some reason it just doesn't compute for me. This past year I was E50 and didn't use it, and I am SE for the upcoming year and want to take advantage of everything I can!

Also known as Priority Rewards.

Access to more seats using Aeroplan miles. For SEs, it's more seats at the regular Aeroplan fixed mileage price, both in Y and in J. In Y, it's simply subject to the flight not being oversold. In J, if there's R space, you can redeem Aeroplan points for the seat.

For non-SEs, the benefit is less valuable as it only applies to Y and costs 2x the regular fixed mileage level. In my experience, Market Fare is almost inevitably cheaper, but perhaps there might be times where a flight is nearly sold out and it might be worthwhile.

Used correctly, this can be a very valuable benefit, especially if you have a lot of miles that you rack up from credit cards.

IKK is limited to 10 per year though, so use them wisely.

KK is the reservations systems mainframe code for a confirmed reservation. "I" is for "Instant". Basically it allows a SE to get any economy seat (assuming positive space, ie: not an oversell) they want for an Aeroplan reservation, instead of being subject to the usual inventory constraints. The theory being, SE's spend enough $$ with AC, and are flying enough that they deserve to at least be able to use the rewards the AP program offers.

There are limits because obviously a SE could obtain millions of points with credit cards or similar, and use the points entirely on tickets that otherwise would only be available with full-Y inventory (ie: $$$$$$, $3000 for a transcon, for instance!). Depriving AC of that revenue.

The IKK also exists for J but in a more restricted fashion, it requires positive R space. Which is still a lot better than what regular rewards get you.