There have been fears of exams being cancelled as well as flights
Exam timetables could be readjusted to help pupils stranded overseas by flight cancellations.
The joint qualifications body said it would be "sympathetic" to those students caught in the travel problems caused by volcanic ash.
There are some practical parts of art exams and oral tests for language subjects which are set to begin which could be rearranged.
However no written GCSE or A-level papers will be rescheduled.
A statement from the Joint Council for Qualifications offered reassurance to pupils worried about missing their exams.
"JCQ and its members are currently monitoring the situation and are sympathetic to those teachers and students who are unable to return to the UK as a result of the current international flight situation."
It suggested that where possible the exam could be rescheduled or else "special considerations" would apply - the same as if pupils were unable to attend an exam because of illness or bereavement.
The problems with travel have caused problems for schools where staff have been unable to get back from overseas holidays.
The Department for Children, Schools and Families said heads had contingency plans to deal with such issues.
But teacher supply agencies say they are under intense pressure to make more temporary staff available.
Teacher supply agency Protocol Education said it had had four-fold increase in the number of calls for teachers at schools in south London.
Capita Education Resourcing said it had seen the number of bookings and calls requesting staff double.
Capita's managing director Simon Taylor said: "I sympathise with the effect this is having on schools; losing one or two members of staff on any given day is difficult but some London schools have reported having more than a quarter of their staff missing."
And Randstad Education, one of England's biggest supply teacher providers, said call levels were higher.
Head rescues staff
Mike Coyne, a head teacher from South Gloucestershire, drove to Germany to rescue five teachers from his school who were stranded on a school visit.
The five were visiting a school in Lithuania during the Easter holidays, as part of a British Council funded trip.
They had managed to get as far as Cologne by train but could not get back to the UK.
Mr Coyne, head of Hanham Abbots Junior School, booked onto a ferry from Dover to Dunkirk on Sunday and drove to Cologne to bring them back in a 28-hour round trip.
"It was my duty to get them back, I had a duty of care," said Mr Coyne.
The school was closed on Monday, but opened on Tuesday, even though three other members of staff were still stranded elsewhere.
Walnut Tree Walk Primary in Lambeth was forced to close on Monday, because seven teachers were stranded abroad.
But it reopened on Tuesday, using a combination of supply teachers and senior staff to cover lessons.
Woodcote High School in Croydon is open, despite having 13 teachers stranded overseas.
Head teacher Mark Southworth said it had been planning to cope with staff absences since Thursday.
"We have 13 teachers struck abroad - we did have 14 but one intrepid member of staff made it in this morning, coming all the way back from Barcelona.
"He was the hero of the staff room and he got a big cheer when he came in."
He said the school had managed to open by calling in favours, asking staff and senior leadership teams to take extra classes.
"The worry is if this goes on. We have got the exams season looming and we have really got to protect those students doing their GCSEs and A-levels."
Staff shortages, due to travel problems, forced Queen Elizabeth Grammar School in Derbyshire to close on Monday. It re-opened on Tuesday, but only for pupils in Years 10, 11, 12.
Some schools are basing assemblies and lessons on the impact of the volcanic cloud.
One teacher, stranded in Spain, has used a webcam to make sure his business A-level business students do not miss out.
Chris Orr, who teaches at Sibford School, in Sibford Ferris near Banbury, was due to fly back from holiday in Alicante last Friday.
A Department for Children, Schools and Families spokeswoman said they were monitoring the situation closely.
"Schools have contingency plans in place and head teachers are best placed to decide how to cover for absent staff effectively and support pupils forced to miss classes."
Has your school been affected by the problems with volcanic ash? Send us your comments and experiences using the form below.
The BBC may edit your comments and not all emails will be published. Your comments may be published on any BBC media worldwide.