A Caravan configured for twelve flying four passengers has eight empty seats. The instinct is to price those eight and sell them. The instinct is mostly wrong, and it is worth knowing exactly why.
What the empty seat actually costs you
Almost nothing in fuel. Eight empty seats add very little weight compared with the aircraft itself, and the fuel difference on a leg of 83.5 nautical miles to Drake Bay is small.
A great deal in opportunity, but only sometimes. The seat costs you nothing if no group of twelve was going to book that day. It costs you a full aircraft if one was.
And something in category fit. If your four-passenger jobs keep going out on a twelve-seat aircraft, the real cost is that you are flying the wrong category — which is a fleet decision, not a seat decision. The specific aircraft is assigned on confirmation, based on passenger count, baggage and the destination field.
Why selling the seats separately is a different business
Charter is quoted per aircraft. We show a "from" price per route; the final fare depends on the date, the group and the baggage, and is confirmed in writing before booking. Selling individual seats to strangers who did not book together changes what you are operating, and in most jurisdictions it changes which rules apply.
That is not a commercial nuance: it is a different authorisation. An operator who starts selling seats to unrelated passengers on a published schedule has stopped doing charter.
Before doing anything in this direction, the question is for your authority and your adviser, not for a marketplace. We run scheduled private flights across Central America; any other destination worldwide is coordinated on request.
The two cases where filling seats does work
When the group grows. A party of four that becomes eight fills seats within the same booking, the same contract and the same rules. It also improves your arithmetic without changing anything about your operation.
And when two bookings share an aircraft by mutual agreement, with both parties knowing and accepting it. This happens on thin routes and it is normal, but it is arranged, not sold as inventory.
The distinction is not semantic. Arranged means both parties consented to a specific shared flight; inventory means seats offered to whoever buys. The first is a conversation, the second is a different licence.
The number worth tracking instead
Not seats filled. Aircraft-days sold.
An operator whose twelve-seat aircraft flies six days a week with four passengers aboard is doing better than one whose aircraft flies twice a week full. The empty seats are visible and the empty days are not, which is why operators worry about the wrong one.
Tortuguero is 53.4 nautical miles from San José: a short leg where the aircraft returns the same day. On those, what fills your month is the number of rotations, not the number of bodies in each.
The useful reframe
An empty seat is not lost revenue. It is spare capacity that cost you nothing to carry, and occasionally it is the reason you win a booking — because the group grew by two and you could still take them.
The operators who chase seat-filling on charter aircraft usually end up buying a smaller category, discovering it turns away groups, and buying back up.
Frequently asked questions
What does an empty seat cost in fuel?
Very little. Eight empty seats add small weight next to the aircraft itself.
Can I sell the remaining seats separately?
That changes what you are operating and which rules apply. It is a question for your authority and adviser.
When does filling seats work?
When the same group grows, or when two bookings share an aircraft by mutual agreement.
What should I track instead?
Aircraft-days sold. Empty seats are visible; empty days are not.
Should I buy a smaller aircraft then?
Only if your history says so. Many who do discover it turns away groups and buy back up.
Is an empty seat lost revenue?
No. It is spare capacity that cost nothing to carry, and sometimes it is why you win the booking.
Let us talk
The specific aircraft is assigned on confirmation, based on passenger count, baggage and the destination field.