Passengers and ages

Passenger types

• A lap infant (infants) sits on an adult's lap: no seat and, in most markets, no separate fare. Send it when the child stays under 2 for the whole trip.
• A seated infant (seated_infants) has a seat and a ticket. Use it when the family wants a seat for a child under 2.
• A child aged 2 to 11 (children) is a regular seated passenger. An adult can travel with several children, and with a child of 2 and a lap infant at the same time.

Search: the passengers object

Counts, and an ages list for every type that has one. Every field is optional: the default is one adult, and a search with no passenger at all (passengers missing, [] or an empty text) is a search for one adult. Counts are JSON integers. "2", "2.0" and 2.0 are read as 2 with a coerced_value warning, and an empty text or null means not sent. A negative count, a fraction, words, a boolean or a number above 99 is 400 invalid_passenger_count. What limits a search in practice are the capacity constraints below.

{
  "adults": 2,
  "seniors": 0,
  "young_adults": 0,
  "children": 2,
  "child_ages": [10, 6],
  "infants": 1,
  "infant_ages": [1],
  "seated_infants": 1,
  "seated_infant_ages": [1]
}

An ages list is a JSON array of integers. A text list ("7,9"), one bare number, and numeric text or an integral float for an age ("7", 7.0) are read with a coerced_value warning; a fractional age (0.5) counts as the years completed (0). An empty text or null means not sent. An age above 17, a negative one, or one that is not a number is 400 invalid_passenger_age.

Ages are not required, and they win over the counts. The API does not reject a count that disagrees with its ages: it changes the search and says so in a coerced_value warning. A missing age of a child, a young adult or a seated infant is reported with a warning that names the age assumed; a missing lap-infant age is not. Measured on the sandbox:

Always check travelerPricing of the first offer against the travelers you meant, and send the real ages.

Capacity constraints

A broken rule is answered with 400. The body keeps its long-standing flat shape (error: "TRAVELER_RULE_VIOLATION", in errors[0].code as traveler_rule_violation), and violations[] lists every broken rule:

{
  "environment": "sandbox",
  "success": false,
  "requestId": "2b773b87",
  "error": "TRAVELER_RULE_VIOLATION",
  "message": "Total seated passengers cannot exceed 9",
  "violations": [
    { "code": "MAX_SEATS_EXCEEDED", "message": "Total seated passengers cannot exceed 9", "max_seats": 9, "seated_passengers": 10 }
  ]
}

The violation codes are MAX_SEATS_EXCEEDED (max_seats, seated_passengers), LAP_INFANT_LIMIT (lap_infants, adult_senior_count) and SEATED_INFANT_LIMIT (seated_infants, adult_senior_count). With no supplier left, the body is SUPPLIER_PASSENGER_COMBINATION_UNSUPPORTED with a limitation object (UNDER_TWO_HOST_RATIO, underTwoPassengers, adultSeniorHosts).

Common mistakes

// Children without ages: not an error, but the ages are guessed (11)
// and the price may be wrong.
{ "adults": 1, "children": 2 }

// Better: the real ages.
{ "adults": 1, "children": 2, "child_ages": [8, 5] }

// A child who turns 2 before departure sent as a lap infant:
// the airline rejects it at check-in, it needs its own seat.
{ "adults": 1, "infants": 1, "infant_ages": [1] }

// Better: a traveler who is 2 at departure is a child.
{ "adults": 1, "children": 1, "child_ages": [2] }

// More lap infants than adults: 400 traveler_rule_violation (LAP_INFANT_LIMIT).
{ "adults": 1, "infants": 2, "infant_ages": [0, 1] }

// 10 seated passengers: 400 traveler_rule_violation (MAX_SEATS_EXCEEDED).
{ "adults": 5, "children": 5, "child_ages": [4, 5, 6, 7, 8] }
// Split the trip into two bookings of at most 9 seats.

Booking: the passenger object

book_flight takes a passengers array with one object per traveler you priced (lap infants included). The list must match the passengers of the search and the offer's travelerPricing: a mismatch is refused by the supplier.

Identity document object

Legacy names for every field are listed in Book a flight.