awesome tips so far ! I cant seem to find the deals most of you are quoting. EX. about the cheapest I can find a return flight is $1500. ( using aircanada.com or expedia )

my schedule is slightly flexable with dates to fly out and home in. Although, I need to be in Glasgow no later than Aug 10th, and fly home no earlier than Aug 19th.
I can fly out of either Toronto or Ottawa, and fly into etiher Edinburgh or Glasgow.