Here are some more hidden features of the ITA software.

The extensions to the itasoftware routing language are accessed by postpending commands after a '/'. There's a wide set of commands available, but there's no description of them available on the ITA web site. Unfortunately, each command applies only to one part of the trip, so they must usually be entered in each box.

EXCLUDE SPECIFIC AIRLINES
Command is "-airlines XX ..."
Ex: prohibit jetBlue or Delta
from: BOS ::/ -airlines B6 DL
to: LAX ::/ -airlines B6 DL

LIMIT TO SPECIFIC AIRLINES
Command is "airlines XX ..."
Ex: consider only jetBlue or Delta
from: BOS ::/ airlines B6 DL
to: LAX ::/ airlines B6 DL

LIMIT TO A SINGLE ALLIANCE
Command is "alliance star-alliance|oneworld|skyteam"
Ex: oneworld carriers only
from: BOS ::/ alliance oneworld
to: LAX ::/ alliance oneworld

EXCLUDE CODESHARES
Command is "-codeshare"
Ex: prohibit jetBlue or Delta
from: BOS ::/ -codeshare
to: LAX ::/ -codeshare

LIMIT DURATION OF ITINERARY, IN MINUTES
Command is "maxdur XXX"
Ex: no more than 5hrs for each part of trip
from: BOS ::/ maxdur 300
to: LAX ::/ maxdur 300

EXCLUDE OVERNIGHT STOPS, AIRPORT CHANGES, REDEYES, PROPELLER PLANES, TRAINS, HELICOPTERS, ANY KIND OF SURFACE TRAVEL
Commands are "-overnight", "-change", "-redeye", "-prop", "-train", "-helicopter", "-surface"
Ex: no overnight stops, no airport changes, no redeyes, no propeller planes
from: BOS ::/ -overnight, -change, -redeye, -prop
to: LAX ::/ -overnight, -change, -redeye, -prop

SET MINIMUM OR MAXIMUM TIME FOR CONNECTIONS, IN MINUTES
Commands are "minconnect XX", "maxconnect XX"
Ex: no less than one hour, no more than two hour connections
from: BOS ::/ minconnect 60, maxconnect 120
to: LAX ::/ minconnect 60, maxconnect 120

EXTRA CONNECTION TIME
Command is "padconnect XX"
Ex: require at least 20 minutes more than airline specified minimum connection time
from: BOS ::/ padconnect 20
to: LAX ::/ padconnect 20

PUTTING LOTS OF THINGS TOGETHER
Separate with commas.
Ex:
from: BOS :: UA UA / f bc=l|bc=y, -redeye, -prop
to: LAX :: UA+ / f ua.bos+lax.yup, padconnect 20, -overnight