Yes it certainly is a fantastic yield in this era of interest rates at unchartered lifetime low's.
In terms of its sustainability. A few thoughts. At the last conference call they noted they had only cut the dividend twice in the airlines history, after 9/11 and the GFC.
Barring another one of those events or some similar sized exogenous shock I think there is a very high probability the dividend is sustainable for the foreseeable future.
Average analyst view is actually for it to increase to 23 cps next year and 24 cps in FY21
https://www.marketscreener.com/AIR-N...07/financials/
As you note, capex for the next 4 years is very benign, mostly about $500m but FY21 under $400m and well below annual depreciation of $567m for FY19 and forecast depreciation of approx. $637m for FY20, (extra $70m expected next year, source, just completed conference call). Over the next 4 years based on my analysis annual average capex is approx. $160m less than depreciation so that gives an interesting insight into their ability to pay ongoing strong dividends in the medium term.
I tend to back out any immediate term dividend, (as partial return of capital invested) from forward yield calculations so my "look through" view on the yield at $2.72 taking a medium term investment view is $2.72 less the almost immediate return of 11 cents = $2.61 net investment for the medium term. 23 cents fully imputed for FY20 = 23 / 0.72 = 31.94 cps gross and on a net investment of $2.61 = 12.2% Gross yield. I am a very happy holder at that level and added more this morning.