I think the Sunday-Tuesday-Thursday schedule for a city is far more attractive than the Monday-Wednesday-Friday schedule.

The latter doesn't permit a good weekend trip, esp. if Monday requires a day off of work, which is an atypical day to take off of work, or work from home, when meetings typically occur. College students also generally have class on Monday.

Also, the Wednesday flight is unlikely to be profitable and it will still sell for $49 the week or sometimes day before the flight.

In May and June, the TTN-CLE schedule becomes a M, W, Thu, F, although the service runs in the evening. Maybe pax will fly one way, and can drive back on Sunday.

United specials between EWR/PHL and CLE generally prohibit Sunday travel, and F9's low fare flights were attractive on that front.

TTN-CVG though switches to the better schedule in May and June from MWF to Su, Tu, Thu

Hopefully F9 gets another plane that it can dedicate for a Sunday TTN-CLE and CLE-TTN, along with other flights. Otherwise CLE might struggle.