You really have to read the individual EO for your state. For example, here in Texas the order says "Effective Monday, March 30, at noon, GA-12 states that every person who enters the state of Texas through roadways from Louisiana will be subject to the mandated 14-day self-quarantine. DPS has been tasked with enforcing GA-12, and the public can expect to see an increased law enforcement presence along the Texas/Louisiana border............to include air travelers coming into Texas from the following locations: California; Louisiana; Washington; Atlanta, Ga.; Chicago, Ill.; Detroit, Mich.; and Miami, Fl."
So in Texas, my interpretation is that if I were to fly my plane back from one of the locations included in the order, I would be mandated to a 14 day quarantine. This applies even if I were to drive across the Louisiana border by mistake, & make an immediate u-turn. DPS officers will be patrolling the borders & airports.