Hopefully not, because the airline that is being struck should not be flying. Therefore, there would not be any passengers.
But, usually picketing events are in front of the airport in various places (all dependent on the individual airport) and in front of the corporate HQ. Also, they will be held at shareholders' meetings.
Most airports limit picketing events to a specified number of picketers and specified places in the airport. I have only picketed at IAH and EWR so I only know those two. IAH let us picket at curb-side check-in, inside ticketing, baggage claim, and passenger pick-up with a maximum of ten picketers per group. We had hundreds of pilots show up so we alternated every ten or so minutes.