FAA and FHWA are the largest of these, therefore most likely to have some sort of program. In addition, many federal Departments and agencies have what usually are called honors attorneys programs. Under these, recently graduated attorneys are hired for a period if time, usually one or two years, to work rotationally in different parts of the organization. DOT has a two year program with eight positions. Rotations may include the Coast Guard and Maritime Administration Chief Counsel's offices, as well as the General Counsel's Office of International Law, which in part is involved in law of the sea and similar matters.
Competition is stiff as only the cream of the law school crop is sought.
After the two years, the potential for permanent hire within the Department is extremely high. Anyone interested in this program should also talk to Charlotte Boeck. The Corporation doesn't have a program, being so small and tight in the budget area. Nonetheless, I would be glad to talk to anyone from my legal alma mater about more details than I've included here.