I searched both google and bing.
It looks like it’s safe for our baby as she will be 3 months old (source: Indusladies.com). For new born, it’s almost a no-no (source: about.com). One factor, I saw from about.com and kidsgrowth.com, is the air quality in airplanes and the potential to exposed her to virus. Quote kidsgrowth:
The air in planes is not filtered and recirculates throughout the cabin. All the viruses and other nasty germs circulating through the cabin will increases your infant’s chances of getting an infection.
Considering all the risk and inconvenience, we pretty much settled on her not travel, another reason is the travel is non-essential.