This didn't work out so well for them when they did this under Reagan.
https://www.politico.com/story/2008/08/reagan-fires-11-000-striking-air-traffic-controllers-aug-5-1981-012292
>To the chagrin of the strikers, the FAA’s contingency plans worked. Some 3,000 supervisors joined 2,000 nonstriking controllers and 900 military controllers in manning airport towers. Before long, about 80 percent of flights were operating normally. Air freight remained virtually unaffected.