If you have high blood pressure any form of travel, including flying, is still possible. (travelandtourismguide.com)
In regular bottles negative pressure forming inside the bottle may cause nipple collapsing and negatively affect a baby (colic). (babygearhub.net)
The advanced air vent system was created to eliminate negative pressure forming inside the bottle as a baby sucks the milk out of it. (babygearhub.net)