Here’s a question for someone who had an issue come up in their life after training and would like to delay starting an airline job while still building seniority. Could someone get hired as a regional or major pilot and then voluntarily ask to be furloughed for a year. During that year they would do whatever they could under their circumstances - either flying or a regular earthly job. When the personal circumstances ease, they would then go back to the airline that had hired them. The point would be to build seniority while circumstances dictate not flying. Would that be possible for a new hire to request at either a regional or major airline?
Airlines hire pilots because they NEED pilots to fly the line. The only time airlines allow voluntary furloughs is if they’re overstaffed (and they are offered to the most senior pilots first, not the most junior). If they were overstaffed they wouldn’t be hiring new pilots. What you’re basically asking is to “cheat” the system to allow you to bypass a lousy schedule and first year pay. Even if the airline allowed that (which they won’t) the union would have a field day. Short answer is definitely not unless you want to join the military and serve your country. For that you could get a leave of absence.
What kind of “issue” would prevent somebody from working? How is working at an airline any different than working at any other job? The answer is absolutely not, being an airline pilot is a full time job, it is not something that you can just flit in and out of as you desire.