Scenario 1 might add revenues to a carrier like UA, DL, AA. US govt. bailed out their domestic airlines and they may again.
For all of my recent vacations, the flights were only in the range of 20-30% of the total cost, which leaves 70-80% of the pie to go to hotels, restaurants, bars, museums, shops, etc. So even if US airlines lose out on an international ticket, the gain from the rest of the local economy will more than make up for it.