I was looking up RAX81 to confirm the type of aircraft. It is based at PTK, but recently when it landed at YYZ it was a C310, but then when it left from there to come to YIP it was a E110. Can someone tell me what may have happened. RAX tells me this was a C310.
Actually it was a chameleon airplane 
that changes based on mood and service of flight.
Seriously though, it could be a typo in the flight filing phase. When a flight plan is filed, it will take any valid type of plane in the filing stage and the FAA computers will accept it and Flight Aware receives that information from the FAA computers.
Surprisingly there is no data base in the FAA systems to cross check this against a tail number.
I don’t think model of plane can change over the years even after modifications? Hmmm. 
Most likely they had to substitute aircraft that day and whoever you talked to at the company didn’t know about the change.
I looked at it, the last flight with that flight number was a week ago as a C310 instead of the usual E110. So, it could also be a schedule change that took place that day or they chartered an airplane and let them use the flight number. In any case 81 hasn’t been used since.
Scheduled carriers file their flight plans monthly based on known data.
If there is a temporary aircraft change for a particular route segment, or even a permanent one after the first of the month, it will not be reflected in the FAA NAS computer until the next month or until a daily manual change in the flight plan is done by the company or a tower controller.
Often the crew will advise the clearance delivery controller of the change and new TAS when they request their ATC clearance. Occasionally when the controller workoad is extremely high or the NAS computer falls behind with higher priorty messages the change will not make it into the system.
Thanks for all your insight. I work for the airport and am not especially knowledgable about aircraft, although I am learning a lot. I especially appreciate how willing those who live this stuff are to share. I have had some experience now with two different purchased aircraft data providers, and with Flightaware. I just find it interesting that this data is so difficult to capture accurately. I am responsible for billing some of the flights that come into our airport and the data collection regarding the flights and ownership is proving to be a significant challenge.
Billing?
So, you’re a good person to know!
I’m not sure how good it is to know me, I’m just a small cog in a big machine, but always glad to help.
A good point to remember here is the aviation system, in it’s operational state, is very fluid.
The FAA’s first priority is getting data to the people that need it first, ATC.
Secondly, the data goes to air carriers with an emphasis on their particular operation.
Thirdly, all other users will get near real time data that is heavily redacted and not necessarily complete. Data is provided as an additional service, whether paid for or not. The point is that third parties such as Flight Aware are entitled to the air traffic information, it is a matter of public record. It is just a fact of life that third party data companies are way down on the pecking order and as such they may not get accurate and up to date information.
If members would like accurate information they may file a Freedom of Information Act request and probably receive a reply in a few months but expect to pay dearly for that Red Sox arrival time in Detroit.
The call sign RAX81 denotes the captain flying that trip royal air has a fleet of 20 & 30 series lears. My roomate from college flew for them a year ago.