For would-be vacationers, this has been the summer of our discontent. In the wake of the pandemic, severe staffing shortages have triggered a crush of disruption: Flight cancellations abound while check-in lines snake out the terminal door. Travelers wonder when the chaos will abate. But what if this isn’t just a temporary hiccup? This summer’s air travel meltdown could well be the canary in the coal mine for the labor shortages we may soon experience across the economy as boomers retire, population growth slows and training lags. To avoid further shortages, we must rethink how we invest in wo…