Possible Clues:

• 'Hasta luego!'
• Chihuahua "Ciao!"
• Bill is first person with Oscar and Sam to meet the trio at Visigoth's Centre in Madrid to say goodbye
• *"Later, Jose!"
• Alternative to 'Hasta la vista!'
• "Later, dude!"
• Later, elongated
• Parting phrase in Panama
• Friendly Spanish farewell
• Western 'so long'