Hi there futurepilot94,
Frankly, the answer to most of your questions is: it depends.
If a pilot starts at an airline as a FO and works lets say 5 years on a particular aircraft, do they then upgrade to a different aircraft as a FO or do they remain on the same plane and become a Captain?
This depends on the company. Outside of the airlines there are often client requirements (Contrails, BARS, etc.) which require minimum hours total, PIC, multi-engine PIC, etc. It is more than likely your first command will not be on the same type. For example, you may start on a Beech 1900D as an FO, but your first command might be a Navajo, or smaller turboprop like a Beech 99 or King Air 200. This will allow you to build your time to the client requirements.
At the airlines, it simply depends on your seniority number and the requirements of the airline at that time. You might be able to bid your current aircraft, you might not. There are a lot of examples of guys simply sliding across the cockpit, while still others slide in equipment. From the guys I know flying for Team Red its 50/50...Team Teal only recently jumped into multiple types, but it'll be about the same.
Also, if a pilot were to become a first officer on a new aircraft, do they receive the pay for a FO for the number of years they have been a FO with that airline or do they start at year 1 FO pay again?
Again, depends on the company and any union contract (assuming there is a union). If the contract is written from a company perspective, then often your pay remains the same (you might be bonded again) or there may be a slight increase.
If the contract is written from a "per type" perspective, then there may be a pay change. Typically, the larger the aircraft, the higher the pay in these cases.
In most cases there will be a wage increase every year for the pay level you are on. Sometimes it matches the CPI increase and other times its a flat rate ($ or %). There will always be a cap, after which there are no more pay increases on that type for that position - normally somewhere between 5 to 15 years depending on how the airline views attrition.
how many different planes would a typical pilot fly in their career? If anybody could give me an example of a typical career path of a pilot with number of years on certain aircraft and at what position
Well, yes - it does depend. If you come up through the ranks and fly with, say Porter, you might fly six types in your entire career: one at the airline and five others as you came up through the ranks.
Add one or two with the likes of WestJet.
Air Canada...a guy I know has been there four years and has already flown the E190, B767, A319 and is scheduled for a B787 class. Another guy I know has been 4-years on the E190 and is not planning on moving on.
Test pilots, on the other hand, may fly upwards of 40 aircraft types.
But here is the thing...after a while you begin to realize that airplanes are just like cars. The switches may be in different places, but you pull back and the houses always get smaller. The differences are in procedures, philosophy and limitations...so from that perspective, you almost envy the guys with less aircraft types because they get to learn their machine and learn it well.