There is a letter in the Taft papers from TR to President Taft in 1910 when there was some agitation at the Mexican border. Roosevelt wrote to Taft demanding that Taft commission him as a Major General, saying he would only serve if it were not “a profitless police duty” and outlining exactly how his command would be set up:
“The division would consist of three brigades of three regiments each.. I have my brigade commanders, colonels, and in many cases majors and captains already in mind….”
Also that year TR went up in a Wright Flyer (a technology he ignored while President) and it was reported that during the flight TR shouted, “War, army, aeroplane, bomb!” and pretended to attack an Army Signals station they passed over.
Pretty funny, in a pathetic way, and not really prescient, as everyone recognized the wartime abilities of airplanes from the start (including Taft who as Sec War promoted the Wright’s efforts). It was more a mark of what Taft observed that TR was “obsessed with his love of war.”
TR’s youngest son Quentin became a pilot in WWI and was shot down on July 14, 1918—the only son of a President to die in combat.