Règle correspondante
United States of America
Practice Relating to Rule 8. Definition of Military Objectives
Section F. Lines and means of transportation
The US Air Force Pamphlet (1976) states:
Controversy exists over whether, and the circumstances under which, other objects, such as civilian transportation and communications systems, dams and dikes can be classified properly as military objectives … A key factor in classification of objects as military objectives is whether they make an effective contribution to an adversary’s military action so that their capture, destruction or neutralization offers a definite military advantage in the circumstances ruling at the time. 
United States, Air Force Pamphlet 110-31, International Law – The Conduct of Armed Conflict and Air Operations, US Department of the Air Force, 1976, § 5-3(b)(2).
The US Naval Handbook (1995) lists airfields, bridges, railyards, docks, port facilities, harbours and embarkation points as military objectives. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-2.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Transportation, US Coast Guard, October 1995 (formerly NWP 9 (Rev. A)/FMFM 1-10, October 1989), § 8.1.1.
The US Naval Handbook (2007) states: “Proper objects of attack include, but are not limited to, such military objectives as … embarkation points … docks, port facilities, harbors, bridges, [and] airfields”. 
United States, The Commander’s Handbook on the Law of Naval Operations, NWP 1-14M/MCWP 5-12.1/COMDTPUB P5800.7, issued by the Department of the Navy, Office of the Chief of Naval Operations and Headquarters, US Marine Corps, and Department of Homeland Security, US Coast Guard, July 2007, § 8.2.5.
During the Korean War, the US Joint Chiefs of Staff informed General MacArthur that mass air operations against industrial targets in North Korea were “highly desirable”. The Joint Chiefs of Staff accordingly designated, inter alia, the following targets: the railway yards and shops at Pyongyang, the railway yards and shops at Wonsan, the railway yards and shops and the harbour facilities at Chongjin, the railway yards at Chinnampo, the railway yards and shops and the docks and storage areas at Songjin, the railway yards at Hamhung and the railway yards at Haeju. 
United States, Letter dated 13 February 1991 to the President of the UN Security Council, UN Doc. S/22218, 13 February 1991, p. 1.
In 1966, in the context of the Vietnam War, the US Secretary of Defense stated:
We are directing the aircraft against military targets, only military targets, and those particularly associated with the lines of communication between North Vietnam and South Vietnam over which they are sending the men and equipment which are the foundation of the Viet Cong effort to subvert the Government of South Vietnam. 
United States, Secretary of Defense, Statement on targeting policy in Vietnam, 2 February 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1966, in the context of the Vietnam War, the US Department of Defense stated:
U.S. policy is to target military targets only, particularly those which have a direct impact on the movement of men and supplies into South Vietnam. These targets include but are not limited to roads, railroads, bridges [and] road junctions … In the specific case of Nam Dinh and Phu Li, targets have been limited to railroad and highway bridges, railroad yards … 
United States, Department of Defense, Statement on targeting policy in Vietnam, 26 December 1966, reprinted in Marjorie Whiteman, Digest of International Law, Vol. 10, Department of State Publication 8367, Washington, D.C., 1968, p. 427.
In 1991, in a report submitted to the UN Security Council on operations in the Gulf War, the United States included “supply lines” among Iraq’s military targets. 
United States, Letter dated 22 January 1991 to the President of the UN Security Council, UN Doc. S/22130, 22 January 1991, p. 1.
In another such report, the United States stated that “the supply lines leading from Iraq into Kuwait” were to be targeted by coalition forces. 
United States, Letter dated 8 February 1991 to the President of the UN Security Council, UN Doc. S/22216, 13 February 1991, p. 1.
In 1991, during a news briefing concerning the Gulf War, the US Secretary of Defense stated that “airfields” were considered military targets and had been attacked. 
United States, News Briefing by the US Secretary of Defense and the Chairman of the Joint Chiefs of Staff, Washington, 23 January 1991, annexed to Letter dated 25 January 1991 to the President of the UN Security Council, UN Doc. S/22168, 29 January 1991, p. 3.
In 1992, in its final report to Congress on the conduct of the Gulf War, the US Department of Defense stated that Iraq’s airfields, its port facilities, and its railroads and bridges had been included among the 12 target sets for the coalition’s attacks. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Chapter VI, The Air Campaign, pp. 96–98.
In the same report, the US Department of Defense stated:
A bridge or highway vital to daily commuter and business traffic can be equally crucial to military traffic, or support for a nation’s war effort. Railroads, airports, seaports and the interstate highway system in the United States have been funded by the Congress in part because of US national security concerns, for example; each proved invaluable to the movement of US military units to various ports for deployment to Southwest Asia (SWA) for Operations Desert Shield and Desert Storm. Destruction of a bridge, airport, or port facility, or interdiction of a highway can be equally important in impeding an enemy’s war effort. 
United States, Department of Defense, Final Report to Congress on the Conduct of the Persian Gulf War, 10 April 1992, Appendix O, The Role of the Law of War, ILM, Vol. 31, 1992, p. 623; see also James P. Coyne, Plan of Attack, Air Force Magazine, April 1992, pp. 40–42.