Be very careful about doing this and make sure to keep a copy of the full fare rules at the time you buy the tickets. During some previous airline strikes, (other) USA carriers tended to declare that all ticket on the routes/times likely to be impacted by the strike were completely nonrefundable and nonchangeable, even at FULL Y (or FULL J, FULL F) fares. Those carriers also tended to zero out inventory in cheaper fare bucket. AA and other carriers could do the same now, for example for all flights to/from/through LHR/LGW, so do not assume.