[0] Aircraft grade aluminum alloy's composition roughly includes 5.6–6.1% zinc, 2.1–2.5% magnesium, 1.2–1.6% copper, and less than a half percent of silicon, iron, manganese, titanium, chromium, and other metals.
[1] Aluminum cans are typically 1% magnesium, 1% manganese, 0.4% iron, 0.2% silicon, and 0.15% copper.
There are a lot of metrics that determine the appropriate use of various grades of aircraft level alloys [2]. I guess from the outside some big considerations are how the metal reacts to temperature change and how well a metal cylinder can handle stress while staying light.
[0] https://en.wikipedia.org/wiki/7075_aluminium_alloy [1] http://www.madehow.com/Volume-2/Aluminum-Beverage-Can.html [2] https://en.wikipedia.org/wiki/Aluminium_alloy