CPAverify minimizes the need to check the website of each State Board of Accountancy individually to determine a CPA's license status. CPAverify, with support from participating State Boards of Accountancy, allows consumers the opportunity to check the status of multiple licenses a professional holds at one website.
Generally, if the airspace is not Class A, B, C, or D, and is controlled airspace, then it is Class E airspace. Class E airspace extends upward from either the surface or a designated altitude to the overlying or adjacent controlled airspace.
1 In NDA, however, the floor of Class A high-level airspace varies between FL230, in what is referred to as the Northern Control Area, and FL270, in what is referred to as the Arctic Control Areas.  Only IFR flight is permitted in Class A airspace, and all aircraft are therefore subject to ATC clearances and instructions.