That titan drop was brilliant. Having altitude kill half your titans wasn't a good start though. You'd think they'd have that part worked out at least, especially when there weren't any apparent AA weapons.
So umm.. all Eren's crew has to do is find one of those syringes, transform one of their own into a titan and have them eat Annie. The hardest thing would be to convince a titan to recognize someone encapsulated as food. Actually.. that might not work. If they move Annie above ground and have some titan eat the encapsulated Annie.. she'd just transform from within and rip the titan apart.