By 1916, a second aero squadron was added, assigned to duty in the philippine islands, and new training facilities were added. In october 1916, plans were laid for 24 squadrons: 7 to serve with the regular army, 12 with the national guard, and 5 for coastal defense, supplementing balloon units for the field and coast artillery. Each squadron was to muster a dozen aircraft. The regular army squadrons were either organized or in the process of being organized by the end of 1916, and all 24 squadrons were formed by early 1917, but only the 1st aero squadron was fully equipped, manned, and organized when the united states declared war on germany 6 april 1917.