| DisabilityInfo | Disability vehicle preferences. |
| MultimodalOffer | Multimodal offer influencers.Traveler and trip information used for targeted multi-modal offers. |
| PassengerPrefs | Passenger preferences including service type, physically challenged vehicle and other vehicle preferences.Service and vehicle information. |
 Passengers | Information about passengers who require the ground transportation. |
 POS | Point of Sale Identification. Identification number of the vendor that has made the vehicle availability request and agency number assigned by IATA, ARC, ESRP or TID.Point of Sale (POS) identifies the party or connection channel making the request. |
| ProcessingInfo | Message processing information. |
| Promotions | Promotion codes to be used to calculate availability.Promotions that apply to a ground transportation service. |
| RateQualifier | Rate qualifier(s) that apply to this availability request. |
| Service | Pickup, interim stops and drop-off details.Pickup, interim stops and drop-off details. |
| ServiceType | An extensible list of service types requested by the customer.Ground transportation service types. |
| Shuttle | Location type, name and address details.Service location details. |
| TPA_Extensions | A placeholder in the schema to allow for additional elements and attributes to be included per Trading Partner Agreement (TPA).Allows extensions to be added to the OpenTravel specification per trading partner agreement. |
| VehiclePrefs | Vehicle type preferences. |
| AltLangID | The alternate language for a customer or message encoded as ISO 639-3. |
| CorrelationID | Allows end-to-end correlation of log messages with the corresponding Web service message throughout the processing of the Web service message. |
| EchoToken | A reference for additional message identification, assigned by the requesting host system. |
| PrimaryLangID | The primary language preference for the message encoded as ISO 639-3. |
| RetransmissionIndicator | When true, indicates the message is being re-sent after a failure. |
| SequenceNmbr | The sequence number of the transaction assigned by the sending system for ordered message processing or message resynchronization. |
| Target | Test or Production target system indicator. |
| TargetName | The name of the Test or Production system. |
| TimeStamp | ISO 8601 encoded timestamp indicating the creation date and time of the message. |
| TransactionIdentifier | Unique identifier to relate all messages within a transaction (e.g. this would be sent in all request and response messages that are part of an on-going transaction). |
| TransactionStatusCode | This indicates where this message falls within a sequence of messages. |
| Version | The OpenTravel message version indicated by a decimal value. |