from Wikipedia on the C17 we bought 4 originally and then later added a 5th, we could of added more at the time as they were available, now the only possibility is the A400 or switching the NATO C17s to A400 and picking up the C17
"On 5 July 2006, the Canadian government issued a notice of intent to negotiate with Boeing to procure four airlifters for the Canadian Forces Air Command (
Royal Canadian Air Force after August 2011).
[123] On 1 February 2007, Canada awarded a contract for four C-17s with delivery beginning in August 2007.
[124] Like Australia, Canada was granted airframes originally slated for the USAF to accelerate delivery.
[125] The official Canadian designation is
CC-177 Globemaster III.
[126]
On 23 July 2007, the first Canadian C-17 made its initial flight.
[127] It was turned over to Canada on 8 August,
[128] and participated at the
Abbotsford International Airshow on 11 August prior to arriving at its new home base at 8 Wing,
CFB Trenton, Ontario on 12 August.
[129] Its first operational mission was to deliver disaster relief to Jamaica following
Hurricane Dean that month.
[130] The last of the initial four aircraft was delivered in April 2008.
[131] On 19 December 2014, it was reported that Canada intended to purchase one more C-17.
[132] On 30 March 2015, Canada's fifth C-17 arrived at CFB Trenton.
[133] The aircraft are assigned to
429 Transport Squadron based at CFB Trenton."
Just order the 16 P8's already though really. The only other country that sucks this bad at military procurement is probably India