Macysmama (forgot name, sorry), Macy and Liam are very lucky kids:)
My lil' one was on about 8 plane rides (usually from AZ to WA) and drove across country twice before he was three years old - not fun. This is not counting all the other extremely long drives we have all taken.
People here have given great suggestions. The plane ride is the trickiest due to the ears. We tried to schedule the airplane ride around his usual nap time, which was harder when he was around three months. We also did our best to keep him awake until the plane ride. We gave him the bottle during take off and landing. It did seem to work but our son still had some discomfort. He usually cried but sometimes it really wasn't that bad. It was usually worse when landing. We also gave him some benedryl and that seemed to work. Everyone has their opinions on using benedryl but it helped my son. When he got older, we packed some of his favorite snacks and gave it to him only during take off and when we were landing. He was so into his snacks, he didn't seem to notice the pressure as much.
Driving across country, I packed all sorts of goodies. We bought new toys that Nathan has never seen before and gave it to him throughout the trip. He is such a good little traveler because we have traveled so much.
Oh, I don't know about the bus ride but when we were on a plane ride, we asked for hot water to soak the bottle in...our son did not like cold milk. We actually had the flight attendant fill the throw up bag with hot water and then we placed the milk in the bag for a few minutes. It worked wonderful!!
It will be a bit stressful but if she starts to get fussy, just do the best you can. The people who get the most annoyed are usually ones who have never had kids. They don't understand. All the other mothers will smile (or may try to give you some unsolicitated advice). At least you know some people understand. You both will be just fine!!