Which bus goes to Lisbon Airport?

[Nolan25]

My friend and I are wrapping up our two-week trip through Portugal and are currently in the Alfama neighborhood with a lot of luggage. Our budget is very tight toward the end of the trip, so we’re looking for the most affordable options to get to the terminal. We’re considering taking public transportation or a special shuttle for a reasonable price. From what we’ve heard, some tourist express buses are significantly more expensive than regular city routes. Could you tell us which city bus number goes directly from the city center to the airport terminal without any transfers?

[Nolan25]

Our departure is scheduled for early in the morning, around 5:00 a.m. I read that the subway isn’t running yet at that time, so we’re relying solely on surface transportation. Which routes use large buses with a spacious luggage area? I’m worried it will be difficult for me to get on the bus with my suitcases.