Carrybee

Carrybee is a invulnerable airship that dispenses enemies in the desert of Mega Man Zero. It appears in Fefnir's stage in which Zero has to protect the Resistance Base from a large attack. After defeating a number of troops, it'll appear dispensing Pantheons, Kerberos, and Shellcrawlers. After defeating or evading the reinforcements, Fefnir jumps out and challenges you. 

Carrybee G
Carrybee G is a modified Carrybee that dispenses Pantheons in Mega Man Zero 3. It's no longer invulnerable. It appears in the desert stage of Anubis Necromancess V.