Furnace Hellkite

Flying is an evasion ability.

A creature with flying can’t be blocked except by creatures with flying and/or reach. A creature with flying can block a creature with or without flying. (See rule 509, “Declare Blockers Step,” and rule 702.17, “Reach.”)

Multiple instances of flying on the same creature are redundant.

Affinity is a static ability that functions while the spell with affinity is on the stack. “Affinity for [text]” means “This spell costs you {1} less to cast for each [text] you control.”

If a spell has multiple instances of affinity, each of them applies.