...yes. It's not like Andrew wandered away - Howard has convinced himself of that - Andrew vanished. Completely and utterly, without trace, from one moment to the next. Abducted by aliens, teleported to a starship, transported in time...at the moment, none of those sound too outlandish. Howard does wait a moment, pausing before he starts the engine. Then he rolls down the window and says self-consciously but in a loud voice:
"Andrew, if you turned invisible, get in the car now. I'll give you 30 seconds, and then we're leaving!"
He looks over at Annette, embarrassed, and shrugs. He waits about 15 seconds, then starts the car, then waits a while longer, tapping his hand on the steering wheel, feeling more and more foolish. Then he adjusts the rearview mirror to look in the back seat. "Andrew, if you're back there already, I swear, I'm gonna..."
The time's up. Howard leans out the window: "Okay, John, I'll follow you!"