In Canada you have very few options. Both Air Canada and West Jet will not take even consider taking a Bass in a Flight Case as baggage. The dimensions are larger than allowable, as is the weight.
They will tell you to take it to the cargo desk.
However, if you're shipping it as cargo, they will require that you crate it. They will also use a forklift to load it, this is not a good idea. To go on your flight they will probably need it to be taken to Air Cargo several days in advance
I've shipped a bass at least 10 times in the past 5 years.
The only way that would work for me was Purolater Ground Service.
In all cases I shipped between the West Coast and various places in Ontario. It took 5 - 6 days, but the bass arrived in good shape.
Just a note here, do not, under any circumstances, use UPS.
I made the mistake of trying them once, they not only lost the shipment twice, but when it did arrive it was very obvious that they had mistreated it. Even though Bass Trunks have wheels and are designed to be easily moved around by one person, they had dragged it across a cement floor and ground off a good portion of the gelcoat.
They also managed to punch several large holes through the Stevenson fiberglass case.
Thank my lucky stars the holes were in the bout areas and the Bass wasn't damaged.
When I took pictures and wrote a letter they gave me the runaround for a few weeks and then politely told me to piss off.
I've never had a problem shipping with Purolater though.
You will find that not all their agents will be cooperative - they're afraid of the shipment - it just looks so big and heavy to them.
Also, the measured dimensions don't tell the whole story.
They will measure the total height and the total width etc without regard for the fact that its bigger one one end than the other.
I ended up on the phone, from the local depot to headquarters once, and the manager at the end of the phone asked me what it looked like. I told him it looked somewhat like a guitar case - only much bigger.
He told the agent to take an average of all dimensions and use that.
I've paid anywhere from $98.00 to $160.00 for the shipment (similar destinations).
An important hint - have the dimensions and the weight ready for them. It usually works best if you fudge the numbers slightly in your favor.
My experience has shown that if you're prepared to tell them what it weighs, and what the dimensions are they will not bother to measure or weigh it.
This will work in you favor.
Make sure the bass is insured so that you don't have to use the shippers insurance. They want an arm and a leg for it.
I always mark the declared value (on the shipping documents) at $100.00.
Too much and they will not take it, and if you're insured properly it's not a problem anyway.
Good luck, it's a problem Bass players face.
We found a solution that avoids this problem . We had a Mario Lamarre neck conversion done.
Works great, haven't had a problem with air travel since.