The option to Generate Sequence Diagram is on operation speedmenus in class diagrams. The Generate Sequence Diagram Expert gives a choice of which classes and implementation details to show. Below is our sequence diagram. Dark rectangle correspond to loop or conditional statements. The final four objects are lowered on the diagram to indicate that they are created as the reservation is made.
Collaboration diagrams are equivalent to sequence diagrams.
To switch from one to another, go to the diagram speedmenu. When an object on a diagram is hyperlinked to another, its name appears in blue. When you create as sequence diagram from an operation, Together automatically hyperlinks the operation to the sequence diagram. Look at your AirlinePD class diagram. You can also create hyperlinks from one object to another directly via the object property inspector.