Below is what someone sent me in 2017 about CO Aircraft sales/purhcase
Purchase of an aircraft by the user of the aircraft –
• Colorado taxpayers are subject to a use tax if the aircraft is hangered in Colorado
• Colorado taxpayers are not subject to a use tax if the aircraft is hangered in
another state. But, use tax may be due to the other state.
• Taxpayers located in another state are subject to Colorado use tax if the aircraft is
hangered in Colorado
Purchase of an aircraft, no trade –
• The sales or use tax is based on the purchase price of the aircraft
The Colorado (CO) state sales tax rate is currently 2.9%. Depending on local municipalities, the total tax rate can be as high as 11.2%.
Colorado is a “home rule” state. Local-level tax rates in the state of Colorado are quite complex compared against local-level tax rates in other states. Colorado sales tax can be levied at the city/county/school/transportation and SPD (special purpose district) levels.
For sales tax registration, Colorado switched systems in October 2010. According to the Colorado Department of Revenue, all businesses must be using a number known as the new Colorado Account Number, which is eight digits. Numbers obtained prior to October 2010 are seven digits. In order to increase the accuracy of tax records, all businesses with seven digit numbers should add a “0” at the beginning of those original numbers. For example, if your account number was L12-34567-0000, your new number is 01234567.
Companies doing business in Colorado need to register with the Colorado Department of Revenue. In addition, several municipalities require registration for the purposes of collecting sales tax.
http://www.taxrates.com/state-rates/colorado/