Airline ticket sales by travel agencies spiked in January, ARC reported.

Total agency sales for the month came in at $10 billion, up 7% year over year. The number of trips booked was 28.2 million, up 6% year over year, according to ARC, with international bookings up 8% and domestic bookings up 4%. The average roundtrip domestic ticket price was $581, up 4% from a year ago, led by a 7% jump in economy ticket prices.

ARC data reflects sales by OTAs, leisure and corporate travel agencies but not airline direct purchases.

"January's agency air ticket sales reflect the optimism for continued travel demand expressed by several North American airlines in their recent earnings calls," Steve Solomon, ARC chief commercial officer, said in a statement.

During those earnings calls, airlines were especially bullish about corporate demand. ARC, however, said that passenger trips issued by leisure-focused travel agencies increased 6% year over year, while trips issued through corporate agencies decreased 3%.