Congressional Budget Office Cost Estimate: H.R. 3328: Cuban Airport Security Act of 2017 [open pdf - 89KB]
"H.R. 3328 would require the Department of Homeland Security (DHS) to report to the Congress on the status of security measures at international airports in Cuba. The bill also would direct DHS to establish an agreement with the Cuban government to permit U.S. federal air marshals to conduct missions on regularly scheduled passenger flights between the United States and Cuba and to allow inspectors from the Transportation Security Administration to access Cuban airports. Finally, the bill would prohibit U.S. air carriers from employing Cuban nationals unless those air carriers meet certain conditions."
Congressional Budget Office: https://www.cbo.gov/