President Donald Trump walks from Marine One as he arrives at Luke Air Force Base, Ariz., Friday for a Defense Capability Tour. (Carolyn Kaster/AP)
Brig Gen. Todd Canterbury, 56th Fighter Wing commander at Luke Air Force Base, greets the president. (Senior Airman Alexander Cook/Air Force)
A member of the military takes a selfie with President Trump at Luke Air Force Base. (Carolyn Kaster/AP)
Brig. Gen. Todd Canterbury, 56th Fighter Wing commander, talks with President Trump Friday about the capabilities of the Air Force and of Luke Air Force Base. (Senior Airman Alexander Cook/Air Force)
Brig. Gen. Todd Canterbury, 56th Fighter Wing commander, briefs the president on the capabilities of the GBU-12 bomb. (Carolyn Kaster/AP)
President Donald Trump talks to a pilot in the cockpit of an F-35 aircraft during a Defense Capability Tour at Luke Air Force Base, Ariz., Friday, Oct. 19, 2018. (AP Photo/Carolyn Kaster)
President Donald Trump engages in a roundtable discussion with cabinet members, congressmen and defense industry leaders Friday at Luke Air Force Base, Ariz. The discussion focused on a variety of topics, including cybersecurity, foreign military sales and technological advancement. (Senior Airman Ridge Shan/Air Force)
President Donald Trump pauses to listen to a reporter's question during a defense coundtable at Luke Air Force Base Friday. (Carolyn Kaster/AP)
President Trump speaks during a defense roundtable at Luke Air Force Base Friday. (Carolyn Kaster/AP)