Yes, you're right! The sentence "With an early start, they should be here by noon" expresses a likely or expected outcome in the future. It's not a guarantee, but based on the early start, it suggests that it’s probable they’ll arrive by noon. So, it's about something you think will likely happen if the conditions (early start) hold.

‘With an early start’ in this case is conditional: it means ‘it they leave early’…

Thanks ma'am and sir?