Can I work for any airline?

No.

In order to be a pilot with Air Canada you must be a Canadian citizen or permanent resident. It will be the same with any other Canadian airline.

In order for any Canadian company to hire foreign workers, they must obtain permission from the Canadian government and prove that no Canadians want the jobs. Canadian airlines have been laying off pilots same as the US airlines and there are lots of Canadian pilots looking for work. No Canadian airline would need foreign pilots or could get permission to hire one even if they wanted to.

Other than marrying a Canadian willing to sponsor you, there is no realistic way to become a permanent resident. If you could qualify as a skilled worker, investor, experience class, etc. you wouldn't be working as a pilot -- you'd although have another profession or millions of dollars. The process also takes upwards of three to five years.

Working for "other (foreign) airlines" -

Two (three) requirements -

(1) Hold a pilot licence issued by the aviation administration of that country -

(2) Have the right to work (by nationality or permanent visa) in that country -

(3) (sometimes also) Know the language of that country -

.

No. You must have the legal right to work in a foreign country to work for an airline based outside the USA. You would either need to become a citizen, or obtain a permanent visa with working privileges. This is not easy to obtain unless you'd like to live someplace in the eastern or southern hemisphere where skilled foreign workers are in demand.

You have to go on your government's act related to the air craft sector.

Yes, you can work for it if your are pilot and , if they let you.