duh. green like teenage lovers between the sheets = inexperienced, not sick. he isn't talking about actually flying, he's comparing the sensation of take-off to the beginning of a relationship, "recycled air" = emotions he has felt before, in other relationships. what he is feeling in this new relationship is exciting and scary and in order to keep himself calm, possibly to avoid being hurt, he's telling himself that it's nothing new, just the recycling of past experiences - stale air
duh. green like teenage lovers between the sheets = inexperienced, not sick. he isn't talking about actually flying, he's comparing the sensation of take-off to the beginning of a relationship, "recycled air" = emotions he has felt before, in other relationships. what he is feeling in this new relationship is exciting and scary and in order to keep himself calm, possibly to avoid being hurt, he's telling himself that it's nothing new, just the recycling of past experiences - stale air