We have some experimental data on this, though, since jetliners and volcanoes both inject sulfur into the stratosphere. The global air traffic halt of 2001 and the aftereffects of eruptions have been heavily studied.

(It would be ironic if the world's response to fossil CO2 emission is to mandate extra high sulfur jet fuel, but nothing would surprise me)

Another example is the https://en.wikipedia.org/wiki/Year_Without_a_Summer caused by the 1815 eruption of Mount Tambora