Sorry, bad Spirit info apparently.... I know at Delta we can rollover $500 a year out of a possible $2600 being set aside.

Here's what the IRS allows, but apparently the company can determine if they want to allow it as well:

$500 Rollover
This FSA regulation gives account holders the ability to "roll over" up to $500 in to the next plan year's account to prevent a large portion of funds from being forfeited. The FSA plan sponsor can elect to allow less than $500 to be rolled over, but the same rollover limit must apply to all participants under the current FSA plan rules. The $500 rollover does not count toward the following year's maximum election amount ($2,600 for 2017), so account holders could feasibly roll over $500 of last year's funds on top of the full election amount of $2,600 for 2017, which would give them $3,100 available for reimbursement for healthcare expenses that year.