Airline Upgrade Eligibility

Three request blocks matter: passenger carries ticketStatus, loyaltyStatus, loyaltyMiles, and fareClass; flight contributes cabinAvailability; and corporate supplies agreementLevel and upgradeEligible.

Gatekeeping happens before any points are scored: with first hit ordering the table returns isEligible false as soon as passenger.ticketStatus deviates from 'confirmed', with dedicated rows mapping 'cancelled' to 'Flight cancelled' and non-'completed' states to 'Check-in not completed', and only the blank catch-all confirms 'Basic eligibility confirmed'.

Running hard disqualifiers ahead of scoring mirrors how upgrade queues work in practice: a passenger without a confirmed ticket, on a cancelled flight, or not checked in cannot take a premium seat no matter their status, so filtering first keeps the scored pool clean. These are operational preconditions, not point tradeoffs, which is why they short-circuit instead of subtracting.

Points for status pair each tier with a mileage kicker under first hit: 'platinum' scores 50 with passenger.loyaltyMiles above 100000 or 40 otherwise, 'gold' scores 35 above 75000 or 30, 'silver' 25 above 50000 or 20, base 'member' 15 above 25000 or 10, and an unknown status scores 0.

Letting tier dominate with miles as a tiebreaker matches how airlines sequence complimentary upgrade lists, where published elite level orders the queue and activity breaks ties within it. The 25000 through 100000 mileage rungs echo familiar qualification bands in frequent-flyer programs, though the point values themselves are internal weighting choices.

Fare paid earns its own points on passenger.fareClass: 'business' takes 30, 'premium economy' 20, 'economy flex' 15, 'economy standard' 10, 'economy basic' 5, and anything unrecognized 0, evaluated first hit down the list.

Ranking upgrade priority by fare value follows standard revenue-based upgrade logic: the passenger who paid more, or bought a flexible fare, represents more yield and is rewarded first. Giving 'economy basic' a token 5 keeps the cheapest fares technically in the queue without letting them outrank flexible tickets.

Contracted business travel adds the final block: a corporate.agreementLevel of 'premier' with corporate.upgradeEligible true scores 25, 'standard' with the flag scores 15, any non-null agreement without the flag still collects 5, and no agreement scores 0.

Corporate deals shaping upgrade priority is common on business-heavy routes, where perks like upgrade priority are negotiated into the account relationship. Requiring the upgradeEligible flag rather than just an agreement respects that only some contracts include upgrade clauses; the residual 5 acknowledges the account without granting the perk.

Supply then reshapes demand: totalScore sums scores.loyalty, scores.fare, and scores.corporate, cabinMultiplier steps from 1.2 when flight.cabinAvailability exceeds 10 down through 1.0 and 0.8 to 0.5 at 2 seats or fewer, and finalScore multiplies the two. Scaling the whole queue by open seats loosens upgrades on empty premium cabins and throttles them while the inventory is still sellable.

Four ordered conditions settle the outcome: basicEligibility.isEligible == false fails immediately and echoes the earlier reason with a score of 0, finalScore >= 75 returns 'Premium upgrade approved', finalScore >= 50 returns 'Standard upgrade approved', and the default row declines with 'Insufficient score for upgrade' while still reporting the finalScore.

Two approval thresholds turn one scale into two grades of outcome, which lets a carrier distinguish a premium from a standard upgrade without running a second model. Returning the score even on refusal is a sensible transparency choice for agents auditing the queue; the 75 and 50 cut points are calibration against the upstream point values.