For the purpose of coordinating and making more effective the field and similar classes of instruction and training in organizations of the National Guard jointly maintained by Alabama and another state or other states during periods of field or similar training as provided under the National Defense Act, the units and personnel of the Alabama National Guard may, if authorized by the federal government, be placed under the supervision and command of higher organization commanders, who have been or may hereafter be appointed from other states, and whose appointment has the approval of this state and the states concerned and the officer recognized by the federal government. This requirement shall not be carried out unless and until the state or states jointly interested in a National Guard organization with Alabama shall have enacted a similar law; provided, that the objects of this section may be carried out with the consent of the Governor, without regard to similar laws enacted by other states, with the advice and approval of the ranking line officer of the Alabama National Guard present at the place of training and instruction and in command of the Alabama troops concerned. For the purpose of fixing the time limits of the periods mentioned in this section, the period of training shall begin when all the Alabama troops concerned have been reported as present in the camp or place of instruction and training and established in their company streets or quarters, and shall end when the Alabama troops concerned have terminated their field training schedule or other program of training or instruction and are reported as ready to leave the boundaries of the camp or training area for their home stations. Alabama troops shall not be required to yield authority and supervision of matters concerning transportation, in or out of the camp or other military area, finance and supply and which concern Alabama only in her relations with the federal government and for which the state is directly responsible to the federal government. The commanding officer appointed from another state, and such other officers of his command as he may designate, who are members of organizations in which Alabama has joint interest with other states and who are appointed and recognized in accordance with laws, rules, and regulations prescribed by the federal government, may, with the approval of the Governor, make tours of inspection and policy visits with the units of their organizations of the National Guard of Alabama, at their home stations or at other places, at such times as are mutually agreeable, it being understood that the state is not responsible or liable for any expenses incident to such visits.