Fluke Fairness Act of 20 21 This bill directs the Mid-Atlantic Fishery Management Council to submit a modified fishery management plan for the commercial and recreational management of summer flounder (commonly known as fluke), or an amendment to the plan, to the Department of Commerce. The plan must establish commercial quotas in direct proportion to the distribution, abundance, and location of summer flounder as reflected by fishery independent surveys conducted by the National Marine Fisheries Service and state agencies; consider regional, coastwide, or other management measures that comply with national standards under the Magnuson-Stevens Fishery Conservation and Management Act; and prohibit the establishment of commercial catch quotas on a state-by-state basis using historical landings data that does not reflect the status of the summer flounder stock, based on the most recent scientific information. Commerce must prepare and consider a plan if the council fails to submit the modifications or amendments. The Government Accountability Office must assess and report on whether the subsequent implementation of the approved plan or amendment complies with national standards.