If in an emergency the President considers it urgent, a temporary installation or fortification may be built on private land if the owner consents in writing.
Structure US Code
Subtitle D— Air Force and Space Force
PART IV— SERVICE, SUPPLY, AND PROCUREMENT
§ 9773. Acquisition and construction: installations and depots
§ 9776. Emergency construction: fortifications
§ 9777. Permits: military reservations; landing ferries, erecting bridges, driving livestock
§ 9779. Use of public property
§ 9780. Acquisition of buildings in District of Columbia
§ 9781. Disposition of real property at missile sites
§ 9782. Maintenance and repair of real property
§ 9783. Johnston Atoll: reimbursement for support provided to civil air carriers