As airlines set lower fares to help Sabah voters return home for next month’s election, many parents say the gesture comes too late for children studying outside the state, who still can’t afford the trip, or can’t miss class.

For thousands of families, the desire for their children to exercise their democratic right is real. But so are the constraints of distance, cost, and academic calendars.

For Rommel Osmand, a self-employed father of two girls...